Calculate Tristimulus Values Xyz Homework


As a painter and professor of art - I constantly come across references that optical colour mixing, as in the art movement "pointillism" as well as ink jet printing involves both subtractive and additive mixing in the eye of the viewer. I completely disagree that two dots of colour, at sufficient distance, can 'additively' mix in the eye. I am not a colour scientist, my knowledge of this is entirely empirical, but I would be interested to hear your thoughts on the matter? Is it possible and if so, how?  (answer)

Is there any known research on trying to find colors outside of the color spectrum?  (answer)

How do one estimate color of an object by just looking at their reflectance data? What is the relationship?  (answer)

The difference between "saturation", "chroma", and "colorfulness" can be very subtle. Can you explain? Similarly, is there any difference between the related terms "value", "lightness", and "brightness"? What do HSV and HSL describe?  (answer)

How come it is easier to see a certain color under low light condition while other colors are hard to see?  (answer)

I project two spot lights on a white screen, RGB=(255,255,0) and RGB=(255,0,255), when both lights combine additively, what "color" I will see? Could I predict the mixture in the RGB Color Space?  (answer)

I am confused by the range value of the Y-tristimulus value. For emissive things, like screens, it is supposed to be the absolute luminance in foot-lamberts (so the range could be 0 to infinity in theory).

If want to compare two colors (via deltaE - which deltaE is the 'standard' nowadays), one from a emissive source and one from a reflective source, can I? It seems like a reflectance number couldn't quite compare to a direct luminance measure, but then how can I compare these two things in a color space?  (answer)

What percent of light is reflected from Brown beer bottle glass? Green beer bottle glass? Clear beer bottle glass?  (answer)

Can females see more colors than males?  (answer)

Artists often find it difficult to identify subtle colors. Eg: is a warmer or cooler than another? Shadow and reflection are very hard. The more you stare the easier it is to convince yourself it is almost any color. I have heard that both saccadic eye movements and bending over so as to look at the subject upside-down can be helpful. Do you agree and do you know of any better techniques?  (answer)

Can you explain the science behind gloss levels on the paintwork of a car. I own an auto reconditioning business and I know using different techniques I try to achieve maximum gloss, even at a microscopic level. Let's say you have the spiderwebbing swirls in your clear coat. Scientifically , what is happening to the light when it hits the swirls as opposed to hitting perfect paint? Is it the law of Refraction or should it be explained another way.  (answer)

Why is light source data normalized to 100 at 560 nm? Is this the source´s relative spectral power distribution or is that something else? Doesn't the normalization affect the computed XYZ or L*a*b* values?  (answer)

I am studying the lightness differences in two types of dental crowns. Is there a minimum ΔL that is not perceived by humans?  (answer)

Does color have an objective existence?  (answer)

If the inability to differentiate blue and black and brown is caused by the gradual yellowing of the lens in our eyes, would wearing another color lens make it possible to see the colors?  (answer)

I'm interested in skin colour and I normally reckon it should lie between 0° and 30° in a HSB colour space. In the Munsell space the Hue shifts for less saturated colors. Are there recognized skin values in the Munsell notation?  (answer)

What is the most visible color for a motor cycle helmet?  (answer)

What education and degree is required to become a color scientist?  (answer)

Why does the S-cone see blue-red (i.e. violet) instead of pure blue? Where does the red come from without the L-cone?  (answer)

Why there is no spectral (pure) colors that can be reproduced by mixtures of other colors? It is just a coincidence of human color vision?  (answer)

I have a very old FM 100 Hue Test Kit (in a wooden box) but do not have a score sheet. I see all of the new kits have software. What came with this kit as it's obviously pre-PC.  (answer)

Is there any way to predict what color an object will appear if I change the color of the light source?  (answer)

Why is it so difficulty to follow the process of saying the color of the word as opposed to saying the word itself?  (answer)

I am a Colorist, want to reduce validation work in laboratory. If I add a quantity of pigment and Tio2 paint, and then measure the shade, we get a certain CIELAB value. From that can I predict CIELAB values given a different quantity of pigment and TiO2?  (answer)

Which would yield the least visual discrepancies, a more chromatic color or less chromatic color?  (answer)

I read that Ansel Adams painted the walls of his home studio a 20 percent gray color to be the best background color to display his photos. Do you have any more specific information about this color? Is it warm or cool gray? Is there an actual paint recipe for this color?  (answer)

I bought a charcoal gray couch - love the color in the store. In my living room it looks dark blue! What color should I use on the walls and accessories to make it look gray again?  (answer)

Can fluorescent colors be printed with cymk printing system? I have Roland printer that uses eco-solmax inks. Are there any RGB or CMYK codes that will work?  (answer)

In textile color matching, Is it possible to match target color in all light source without metamerism. If so what will be the possibility percentage?  (answer)

What does a white balance actually do?  (answer)

What makes a color bright?  (answer)

I study the topographic influence on snow. When an individual looks at snow in shadow, they are actually seeing blue light, yet they state they see white. Is this based on learned experience of color? What effect does the question have, i.e. "What color do you see", vs. "What is the color of the snow?"  (answer)

How does a flower´s color help it survive?  (answer)

Many auto accidents happen in early morning and late in the evening when it is dark outside. Does the vehicle color have anything to do with this? What automotive paint color is easiest for the eye to see when it is dark outside? How about in daylight?  (answer)

Although our sun is often depicted in artwork as "yellow", I have heard that it is actually "white", and that is why a white piece of paper appears white. Is this true? If so and we lived in a solar system with a different type of star, such as a red dwarf or a blue giant, would any objects appear "white", or would they take on the cast of their light source?  (answer)

Imagine driving down a street toward a traffic light. How fast would you have to go so that the red light (700 nm) would appear green (500nm)?  (answer)

Is there a way to measure gloss with a spectrophotometer or is it necessary to have a glossmeter? Is there a conversion between CIELAB values and gloss?  (answer)

How can I avoid metamerism?  (answer)

What are L* a* and b*? Are they constants? If not, how can I find those values?  (answer)

Where can I find calculator or software for LRV?  (answer)

We are told that Red, Yellow, and Blue are the "primary" colors, and that you can make all other colors from them, but those 3 can´t be made by combining the others. In additive systems, it is red and green that combine to make yellow. Is there something inherently special about red, yellow, and blue, or are they considered "primary" only in the sense that the most basic medium of color manipulation is a subtractive system?  (answer)

When we compare luminosity of different hues, we find that blue is a relatively dark color, and yellow is a relatively light color. Do hues have an inherent luminosity independent of human perception?  (answer)

I am trying to emulate a smaller-gamut RGB color space on an LCD display using a 3x3 matrix, and I can not seem to figure out the general-purpose way of doing this. You reference Poynton´s book in a similar FAQ but he skips over the process and just spits out the answer for some important cases.  (answer)

Is there is a device that can measure liquid gravure ink spectral transmittance? I need a method to confirm ink recipe components in a liquid ink sample. I could use a faster option than the traditional draw-down proofing method.  (answer)

How many lights are metameric to white light reflected from a paper?  (answer)

I use the Munsell Color Books to develop color harmonies for clients to use on short term projects. Is there an inexpensive way to get swatches or chips that match the Munsell notation? Can I print them?  (answer)

Are there studies of floral arrangement preferences of dichromats?  (answer)

How did the CIE 1931 color matching experiments evaluate the whole gamut when we know that the RGB color gamut is a subset of that of the human eye? In other words, we know there are colors that cannot be matched by the RGB lights. How did they get around this?  (answer)

The sensitivity of the human eye to color difference is greatest at approximately 550 nm. However, in interpreting the MacAdam ellipses , it would appear that humans are least sensitive to differences in color in this region. Why?  (answer)

I measure timber colour using a Minolta Chromameter CR-400. I want to compare my values with those of other woods whose colors are listed in percent Luminance, Dominant wavelength (λ)and percent purity. Can I convert these values over to CIELAB?  (answer)

Is it possible to scientifically determine the original colors in an old black and white stereoview photograph if some of the colors are known?  (answer)

How does aging affect color perception? Are older people able to discriminate brighter colors or softer colors better?  (answer)

What wavelength(s) are used in the calculation of Gardner color?  (answer)

Is it possible to explain color to a blind person if thay have never experienced it? Can the brain of a blind person assign a color to something if they know the shape but not the color?  (answer)

I need to predict CIELAB of a color at different thickness. The color is transparent and .01 inches. How do I predict LAB values at thicknessof .121?  (answer)

Why do different pure hues have differing lightness values?  (answer)

In his 1943 OSA paper "Specification of Small Chromaticity Differences" MacAdam describes constants g11, 2g12, g22 and gives values for them in graphical form. Is there a source for this data in conveniently tabulated form?  (answer)

I need a device that will give me color readings at an observer angle of around 45 degrees or so that will pick up almost 100% specular reflection.  (answer)

Why is it not possible to get an accurate ΔE colour measurement on a metallic powder coating?  (answer)

At what luminance (Candela per meter squared) in the ambient environmental light does scotopic vision turn to mesopic vision, or at what point can we start to see color? And at what point can we see the majority of colors?  (answer)

What is the most common first color that children recognize? The second?  (answer)

We have a WWI aircraft we are recovering with fabric that requires a dark green paint for the wings. This aircraft is flown a lot and displayed to the public outside quite a bit. The problem is that this paint absorbs sunlight heat dramatically which reduces the life of the doped fabric, causing it to shrink prematurely and it is fairly expensive to replace. Would a primer coat of silver dope or white help reduce the absorption of the heat into the fabric under the dark green paint?  (answer)

Do you know the origin of a measurement called the "flop index", which is defined as flop index=2.69(L15�-L110�)^1.11/((L45�)^0.86). My Xrite M68II reports this metric, however, X-Rite does not explain the source of this equation. Do you know where I might find the source of this equation, or another good way to mathematically explain the color difference at several angles?  (answer)

What is the differance between additive color and subtractive color?  (answer)

I am turning my formal dining room into an art gallery. We painted today and it is too bright. The way it looks now all you will see is the paint color and not the art. What are the best colors to paint a gallery, given that all the pictures are of different color schemes?  (answer)

Scientifically speaking, is black a color? Is white a color?  (answer)

In comparing light bulbs based on their color temperature, how much difference in color temperature is needed before an average person can notice that difference?  (answer)

Are there any specific details in 45:0c reflectance measurement, such as the effect of distance between detector and sample or distance between light source and sample? Are there restrictions on the circumstances, like the color of the floor on which we put our sample?  (answer)

Is there any approximation to convert between Hunter Lab (illuminant C, 10 degree observer) and CIELAB (illuminant D65, 10 degree observer)?  (answer)

I received data from two sources. The first measured Hunter Lab on light source C under 10 degrees, the second measured CIELAB on light source D65 under 10 degrees. I don't have the spectra. Is there any approximation with which I can convert between them?  (answer)

What observer for XYZ values can be used in CAM02, 2 degree or 10 degree? Some articles use 2-degree observer, the others use 10-degree observer.  (answer)

I am looking for the differences between red, blue, green, and yellow dye. Can you tell me anything different about them, other than they are different colors?  (answer)

What part of the spectrum helps grass grow?  (answer)

Why does the color of a crayon or colored pencil look a different color on paper? For example, some purples show up blue on paper.  (answer)

Would a spectrophotometer be able to accurately read the color differences between chrome plated surfaces? (ie. mirror-like finish) What settings or type of instrument would best achieve this?  (answer)

Is it possible to quantitatively describe a color just by its reflectance or radiative spectrum?  (answer)

How a mixture of R, G & B single wavelength sources (such as RGB laser) can produce white light even though they do not cover the whole spectrum?  (answer)

Is there a formula for calculating Delta E in Munsell?  (answer)

I would like to convert from CIELAB coordinates into the approximate spectral red green and blue component curves. Is this possible?  (answer)

Why do we see colors when we spin a disc that contains figures in black & white?  (answer)

When job requirements demand color discrimination, how often should employees be tested on their color perception?  (answer)

Is there a color model which would allow me to do the following? Given L*a*b*/XYZ/whatever coordinates of a color stimulus, given specified viewing conditions and color, what is the shape/size of the JND "ellipsoid" around the color, and what are the directions of the hue/chroma/lightness axes?  (answer)

Is there still a copyright on the Munsell color system? If so, who owns it?  (answer)

Which light colors are absorbed by a yellow tulip?  (answer)

A one dimensional halftone cell has 50% coverage with reflection density 2.0 and 50 % coverage with reflection density 1.0. How is L* calculated for this cell?  (answer)

Are you aware of any software packages or even just charts, that list Munsell colors by both code and name?  (answer)

What colors (in order) would best absorb a green 529nm laser light?  (answer)

Could you please tell me if there is any function that computes the chromatic adaptation and the color appearance for the various types of color deficiencies?  (answer)

How could I provide (or display) the approximate color of a star given it's Kelvin temperature?  (answer)

I am interested to convert a hex html or decimal rgb value to cie 1931. How can I do this?  (answer)

Is 0.05ppm a suitable tolerance for measuring absorption on a spectrometer for beverages? When is it no longer a visible difference to the naked eye 1ppm, 0.1ppm, 0.01ppm, etc?  (answer)

What is the best color to paint behind a High Defintion tv mounted on the wall?  (answer)

What dyes are mixed to get Dark Shell Gray?  (answer)

I am a retinal surgeon. We sometimes stain the retina with trypan blue in order to highlight superficial membranes that need to be peeled (over the retina). Is there a colored contact lens that I could wear that would highlight the blue spectrum more so that it would be easy to see faint staining on trypan blue on the retina?  (answer)

I would like to come up with a color scheme that assigns an absolute color value to common color words. In this scheme I would want scarlet to have a distinct and absolute value different than crimson or puce. Is there any site or program that has assigned absolute color values to the English names of colors?  (answer)

We measure several prints for our printer characterizations. Two questions: (1) what is best space to average - spectral reflectance, LAB or XYZ and (2) if we wanted to do a weighted average to reduce the weight of data which tended to be "inconsistent", how would we best do that?  (answer)

In the CIELAB color space, what is the approximate difference for each of L*, a*, b*, and ∇E that most people would not percieve as a different color.  (answer)

Are there guidelines or rules of thumb for how colors are perceived as "dominant" in an image? Are there differences in the perception of color dominance among different colors? If so, how is this described in the CIELAB color space?  (answer)

Where can I find a chart showing color names, the colors themselves and CIELAB color coordinates? Ideally, this would also show the RGB color coordinates. I have found many RGB charts like this but none with the CIELAB coordinates.  (answer)

Are there established color values for the color of skin for various ethnic groups (like Lab or Munsell for example)? This is for a makeup manufacturer who wants to design packing for specific groups of people.  (answer)

I dyed 100% cotton red, yellow and blue and placed them in direct sunlight for a week. The red appeared to fade the most, but I can't explain why. Can you help?  (answer)

Why does red disappear when viewed behind red glass?  (answer)

Are grey shades actually constant, because they are nearly achromatic, or is there something about eye biomechanics that create a visual perception not in agreement with spectral readings?  (answer)

I need to know the Munsell color for 'school bus yellow.' The unsourced quote I have says it is 9.4YR, 7.5/9.2.  (answer)

What does LCC stand for in the color science world?  (answer)

Where can I purchase a poster size print of the CIE 1931 Chromaticty Diagram? I realize that the diagram is only a 2D projection of 3D matching data however I still find it useful to illustrate some of the other attributes of the data depicted (color mixing, color temperature, color gamuts)?  (answer)

At what distance, target size and viewing conditions (illumination level/type) does the HVS's ability to resolve color breakdown? Put another way, what is the "chromatic" resolving power of the HVS and how is that defined in terms of distance, size, viewing conditions?  (answer)

Is black a natural color or is it just a very dark brown that people just see as black?  (answer)

We would like to know the complete Reflectance Measurement principle and formula for the dual beam color spectrophotometer including Light trap, PTFE standard and sample.  (answer)

Is there a relationship between visual lightness (when we judge lightness of color) and Light Reflectance Value (a measurement that is expressed mathematically?  (answer)

I am a massage therapist. After a massage a customer said that when I had massaged her on a certain part of her body she could see a certain color, for ex. red, & at another spot she saw the color blue. Is there a reason to this?  (answer)

How do you find a RAL equivalent of an NCS colour reference?  (answer)

Why can't humans see ultraviolet or infrared energy?  (answer)

What color is chroma key paint for green screen back drops?  (answer)

Is it possible to determine the ink densities (or transmissivities) in a small area (~20 mm^2) of a four color image (CMYK) from its reflectance spectrum? The relative areas of coverage and overprint of the inks are not known. Illuminant and substrate spectra are available.  (answer)

How would I measure the yellowness of the sclera (whites) of the eye? Also, what instrument would be an appropriate measure haziness of the cornea?  (answer)

What is the color temperature that makes the road most clear during driving, even under unconditional weather?  (answer)

How do I match the actual fabric color in PhotoshopTM? Images are digitally shot, and the final output is four color offset printing.  (answer)

What is the theoretical principals of the color change test in chemistry?  (answer)

I am interested to convert a hex html or decimal RGB value to CIE 1931. How can I do this?  (answer)

Is 0.05ppm a suitable tolerance for measuring absorption on a spectrometer for beverages? At what concentration is the difference not perceptible?  (answer)

What would an acceptable max display luminance setting be for a display that does not see direct sunight or much ambient light so that colors and text are easily readable?  (answer)

What is the unit of the viewing angle? Is it degree, radian or steradian?  (answer)

Using the color bar on Powerpoint 2003 I drag the brightness bar on the Device RBG mode, I get a darker color of apparently the exact hue. Is the hue is truly staying the same? Also, if I drag from R 200, to R150 to R50, is it decreasing in the amount of red equally in each interval?  (answer)

"The Desktop Color Handbook" mentions using a "light source color rendering card" which has patches that look the same under light of the appropriate CCT, but different under other lights. Do you know who makes such cards, or how one could create one?  (answer)

I am a Color Technician for a woman's retailer which specializes in black, white, and neutral only clothing. We test our associates with the Munsell 100 Hue test. Is there a similar test to evaluate for neutrals only?  (answer)

How can I convert RGB or CMYK shade to Pantone?  (answer)

Is there an accepted universal standard for the calibration of color Spectrophotometer? Are there white standards available with certified reflectance values?  (answer)

Are there maximum/minimum values for a* and b* like the min and max for L*?  (answer)

Is color a quality in physics?  (answer)

I have noticed a couple of different species of early-flowering trees have pink blossoms which turn white literally overnight. It is the speed of the process which is intriguing. Do you know how it works?  (answer)

Do you know where I can purchase Hess Ives Color standards, both physical standards and papers publications?  (answer)

How can tulips be so many different colors when they are the same plant?  (answer)

Is there such an instrument as a hand-held spectrometer for measuring the color temperature of light sources? If so, how much do they cost?  (answer)

Densitometers can be purchased with or without polarizing filters. Why are both types used? Which type provides the best correlation to perception?  (answer)

How do you convert ΔL ΔC ΔH values for colour differences in CIELCh to the equivalent ΔL Δa Δb colour difference values in CIELab, when you do not have access to the absolute values for the original measurements?  (answer)

Are there some basic averages for the LRV of human skin?  (answer)

At what age do children develop good color perception?  (answer)

Can you define what is Multiflux math model used in color mathing?  (answer)

I have used three online color space conversion calculators and I get three different sets of numbers when I convert from XYZ to RGB. What's happening? Who's right?  (answer)

Can light be a "Brown" color? If not, why not?  (answer)

What is the RAL number for PMS 268 plum? I've attempted to find a cross-reference tool and have not been successful!  (answer)

When purchasing an encapsulated Haz-mat suit, Level A, what colors have the best visibility for the different environments in which they might be used, i.e, sandstorms, snow, heavy rain, thick smoke, etc.?  (answer)

Roughly how large is the overall remaining perceptual non-uniformity of color tolerances in CIELab space, when using the ΔE94 and ΔE2000 color distance formulas? (as compared to the 6:1 non-uniformity of simple ΔE*ab)?  (answer)

How can I have someone create a paint for me using a theoretical spectral reflectance curve?  (answer)

How does chameleon paint (i.e. paint which color depends on viewing angle) work? What is its composition?  (answer)

How do I calculate the dominant wavelength of a color sample with X,Y,Z or x,y? I do not want to draw it in the colorspace.  (answer)

Why does your hair change color during the season?  (answer)

How to convert CIELAB data to Yellowness and Whiteness index?  (answer)

Which minimizes solar heat absorption better, polished aluminium or white paint on it?  (answer)

How does the eye determine the various colors of visible light?  (answer)

Could you please tell me, what color would 1.2Y 6/11 be?  (answer)

Why do black clothes appear blue in the artificial light of a clothing shop? Then when you take the item into natural light it is black? Why is that?  (answer)

What type of Pantone Guide shall we refer to & which instrument is suitable to measure the values of colour on aluminum foil with a flexo printing process? Since Aluminum has glossy as well as the matt finish then is there any need to change the settings of the instrument?  (answer)

We print on Aluminum foil with a flexo process. What type of Pantone Guide shall we refer to & which instrument is suitable to measure the values of colour? Since Aluminum has glossy as well as the matt finish then is there any need to change the settings of the instrument?  (answer)

How do I convert from spectral reflectance (from a hyperspectral imager) to CIELAB colorspace?  (answer)

Can a consumer grade flat bed scanner be used as a colorimeter?  (answer)

The lighting goal for our new indoor shooting range is to have 100 footcandles of light on each target. Our question is this: should the walls and ceiling around the target be light in color or dark in color?  (answer)

Can you suggest an ideal color scale for a digital elevation map to be printed in a scientific paper? Is it possible to have a color scale that looks good in color and in black and white?  (answer)

Suppose I introduce the same amount of noise in individual channels of a YUV image of 420 format (chroma has been downsampled). Which image is the most noticeable, the one with noisy Y, U, or V?  (answer)

Can you point me to the actual formula the Photoshop Hue/Sat tool is using to change given colors in an image?Can you point me to the actual formula the Photoshop (tm) Hue/Sat tool is using to change given colors in an image?  (answer)

What are the colors of a complete spectrum? (Starting with the color with the longest wavelength.)  (answer)

What color measurement system would be best to define colors for a liquid, to be described in a US patent?  (answer)

Why is blue ink most commonly used for writing?  (answer)

What is the difference between the L*a*b* values and the L a b values when using a Minolta colorimeter?  (answer)

Do you do research on ink jet printer color consistency? We are interested in printing solid colors for visual evaluations. We have a high-end ink jet and use photo paper, but we see color differences of up to 0.5 Units ΔE* between prints using the same printer, inks, profile and paper.  (answer)

My spectrodensitometer states its measuring geometry is 0/45, and its standard observers are 2 and 10. Are these angles related? Which should I use?  (answer)

Is there a way to determine what a symmetrical circle 1% dot, 120 line screen should measure? I am looking for a published table or a equation as I need to determine this on several different screen rulings.  (answer)

I am working on a plastic matched automotive black (GM 848) where the color is visually darker, but it measures LIGHTER than the standard. Can you please explain why?  (answer)

What is the mathematical equation to convert Lab or XYZ to Density?  (answer)

I sometimes catnap at my computer or while reading and when I wake everything looks green tinged for about 20 seconds. Why?  (answer)

Does the color of a laser affect the velocity of the light wave projected by the laser?  (answer)

What is the physics behind a blue-yellow polarizer such as the Singh-Ray Gold-N-Blue filter which photographers use to add yellow or blue highlights to polarized parts of a scene?  (answer)

Is is possible to convert R, G, B values of an image captured using a flatbed scanner to densities? I can convert R, G, B to CIELab using the ICC profile of the scanner. Is there a way to convert CIELab to Densities?  (answer)

Where could an art reproduction facility obtain an optical device that used spectral-based imaging?  (answer)

We know density is derived from the transmitted spectral power distribution. Can you suggest a reference that provides the responsivity functions for Status A and Status M densities, as well as the specific function for the calculation of density? Also, what is the proper illuminant to use?  (answer)

What is "camera gamma" and its relationship to NTSC/HDTV video?  (answer)

How does coloured text affect accommodation?  (answer)

How can I meaure the color of clear solutions? We want an objective measurement (wavelength) of colors of various juices and wines.  (answer)

When choosing an umbrella, what color is best to protect yourself from UV light?  (answer)

I am teaching color theory to our press operators and I am wondering if there is a full color spherical L*a*b model illustration that I can download, and if necessary purchase.  (answer)

I would like to know if the color of the water (by adding food color dyes) will affect the absorption rate of water and thus the color of the white flower over time.  (answer)

What is the Kubelka Munk Theory? What its use in textile dyeing process? Would you please provide me any literature on the Kubelka Munk theory?  (answer)

Is there an existing paint industry standard system for expressing (and thus potentially matching) all the visual characteristics of a metallic or metallic flake paint, whether one-coat or two-coat (colored transparent over metallic or flake)?  (answer)

I am trying to calculate the colour of a coating. I have a graph of wavelenth versus reflectivity. Is there a simple way to convert this graph into RGB values or some similar standard?  (answer)

Since a mirror reflects most of the light that falls on it, as does any white body, what is the difference between the two?  (answer)

I know that the color of a body depends upon the color that it reflects. What causes some bodies to be transparent, others translucent still others to be opaque?  (answer)

I found a source that says an RGB of 194, 32, 11 for Calder Red. Can you tell me what proportions of red, yellow, and blue paint should be mixed to get that RGB?  (answer)

Where can I buy Baker-Miller pink paint?  (answer)

I want to make a slate grey color from white exterior latex paint. What additional colors and quantities of color will I need to mix?  (answer)

This pertains to colors being used for home theater projection screens. Neutal grays have been suggested as the best color since they should not shift the color of the reflected image. Munsell grays are reported as neutral for illuminant C. What would the RGB value be for Munsell N8 and N9 under D65? One source lists N8 as 202 202 202 (L*ab- 81.3256 0.0044 -0.0087, Yxy as 59.0619 0.31272 0.32900). Is this correct?  (answer)

I am an artist interested in painting with photochromic inks or paints. Do you know of a supplier?  (answer)

We have two items painted with Munsell N7 which are significantly different in shade. Is this normal? How can I measure if the differences are within specification?  (answer)

I am building a pit solar greenhouse and need to decide what color to paint the non-glazed walls. White would be the best for reflection onto the plants but I am also looking for more pleasing colors. What is the best color for growing plants?  (answer)

Why isn't E point (x=0.3333 - y=0.3333) used as a standard illuminant for color matching and ΔE?  (answer)

I am working on honeybee color vision. Using a honeybee specific color diagram, we know how to calculate dominant wavelength. How do I calculate the dominant wavelength of a color sample which resides in my color diagram in the "magenta" (or purple) zone.  (answer)

Why are the colors of Christmas typically red and green?  (answer)

I work for an automotive finishing company and use an X-rite MA68II for measuring color. Which should I use, L*a*b*, or L*C*h�? Everyone seems to use L*a*b*, but I'm not sure why.  (answer)

How long does it take for your brain to recognize color?  (answer)

Can you provide a mathematical formula to convert a RGB color value in CMYK color value?  (answer)

How do mood rings work?  (answer)

At what illuminant temperature are Munsell neutrals (N6, N7, etc.) designed to be neutral?  (answer)

Obviously having a single colour on two different stimuli (each encompassing a different meaning) on a workstation will cause confusion. What are these problems from a psychological, cognitive, or ergonomic perspective?  (answer)

Are the colors that we see during the day, present at night - only we cannot see them? Or are the colors that we see during the day not present, or altered, because of the low light?  (answer)

What are the names of pigment suppliers who mfg or distribute metameric pigments?  (answer)

What are the evolutionary advantages and disadvantages of impaired color vision?  (answer)

I am developing paint color regulations to help buildings constructed on mountainsides blend into their surroundings to minimize their visual impact. What maximum LRV do you recommend for an environment typically consisting of darker browns, grays, and greens as the "base" colors in order to keep buildings from "standing out"? What would be the most appropriate instrument for measuring the LRVs of paint/stain for enforcement purposes?  (answer)

How does the color of a room affect people's moods?  (answer)

What are the equations for McAdams ellipses? Are they location dependent in the 1931 chromiticity diagram?  (answer)

It makes sense that I should want window glass with the highest Color Rendering Index available in the performance category that I need; but how do I judge the relative CRI when all options are between 87 and 95?  (answer)

What mixture of acrylic painiting do I need to achieve a copper tone?  (answer)

Can CAM02 to predict Appearance Correlates of a color on different colored backgrounds?  (answer)

Is it proper to state a Munsell notation for a metallic or pearlescent color, or is Munsell a solid color only notation system?  (answer)

Is it possible to draw plankian line in CIE diagram? How?  (answer)

Is there any source of spectral reflectance data for samples in the Munsell Book of Color?  (answer)

Does the Munsell system account for the Helmholtz-Kohlrausch effect?  (answer)

How closely do the Munsell Renotation data reflect the actual tristimulus values of samples in the Munsell Book of Color as viewed under Standard Illuminant C?  (answer)

Why does the sheen of a finish affect the appearance of a color? Do the wavelengths of color get magnified, refracted, or intensified as the pass through the layers of a paint film?  (answer)

Can you explain the difference between value and luminance? Is Light Reflectance Value different than luminance?  (answer)

I understand that the visible spectrum is comprised of the wavelengths red, orange, yellow, green, blue, indigo and violet. Combined they make up white light. So does that mean that white is then a wavelength too? Do all the other colors/wavelengths add up to something that we recognize as white?  (answer)

Does the color of your hair affect it's ability to keep your head warm?  (answer)

What's a good reference for information on the Munsell system?  (answer)

Where can I buy Color Standard for measurement calibration?  (answer)

To measure process color is it better to use a spectrometery or density, hue, and gray?  (answer)

Where can I find absorption or reflectance data for inorganic chemicals or pigments?  (answer)

Is there an index for the degree of yellowing? I want to characterize the degree of yellowing in trees as an indicator of poor health from aerial RGB photographs.  (answer)

Please give an example of how to begin with a tertiary color,subtract one color and then subtract another color but don't end up with a primary color.  (answer)

Where can I buy the Munsell color chart that has the 14 samples used for CRI tests?  (answer)

Where do the beautiful colors of fireworks came from?  (answer)

Why does the greenery of parks and gardens look beautiful to our eye? Please elaborate with regard to perception and function of the eye.  (answer)

Do you a reference for this equation used to get color decimal value from RGB values: "color_code = (r*65536) + (g*256) + b"  (answer)

How precise areMunsell color charts meant to be read?  (answer)

What makes colors fade in plastics? What part or parts of the light spectum?  (answer)

Are there any instruments or methods which measure the intensity of gray color?  (answer)

What the physical meaning of sharper cone reponse in CIECAM02?  (answer)

How do paint colors affect the room temperature?  (answer)

How can I mathematically find the best match for a CMYK color from an array of CMYK colors?  (answer)

I have some images taken with a digital SLR at the wrong white-balance setting (tungsten instead of daylight). Is there a fixed set of RGB correction factors that I can apply to the entire batch?  (answer)

Why do boys choose blues, grays, black, and browns when coloring and girls choose more brighter colors like greens, reds, oranges when coloring?  (answer)

Do some people, through genetics, have dramatically different "rods and cones" in their eyes and see colors totally differently than "most people". This does not include colorblindness, but that some people might see red as yellow and blue as orange, etc. Is this true?  (answer)

I am trying to establish a color system criteria for silicon parts which are white. What do you suggest in setting up a criteria for the color white?  (answer)

What is meant by plankian locus? What is its importance?  (answer)

Are there any estimates of the probability that a photon impinging upon a cone photoreceptor will be absorbed by the visual pigment within the receptor? How does this probability change as the radiance is increased so that more of the pigment is in the bleached state?  (answer)

Can a person with a color deficiency learn colors and shades and be able to distinguish differences even if they are not able to see the exact color that a normal vision person might see?  (answer)

Would it be possible to correct color blindness (for computer users) by measuring a user's color sensitivity at various wavelengths, then adjusting the output of the monitor to compensate for it?  (answer)

How do I calculate whiteness index (WI by ASTM standards) if I don't have a spectrophotometer but am in possession of reflectance data for materials that have

I am a massage therapist trying to do research on what color is best to have in a massage room and how it affects the client, such as improves relaxation, promotes healing. Any guidance?  (answer)

Does a sheet of colored glass reflect, refract or absorb light? Or all 3?  (answer)

Could you possibly tell me the formulas for the harmonic equivalents (tones) of red, orange, yellow, green, blue, violet?  (answer)

I need a fairly fool-proof way for a moderately skilled technician to measure a large number of samples and present the data using the CIECAM02 coordinates. I am willing to buy a new instrument/software. Any thoughts?  (answer)

Is pink a shade of red?  (answer)

I am studying the colour of abalone shells. How can I statistically differentiate cbetween two shells? Eg: this shell is bluer than that one. I plan to use digital photos, D65K light with the camera at the normal angle.  (answer)

Does the color of one's eyes (light colored vs dark color) have any effect on vision?  (answer)

Can the color of the bedroom walls prevent proper sleep? My husband sleeps fine in a blue room, but has trouble in a red room (same bed!).  (answer)

Are car color choices determined by age, gender or ethnic group?  (answer)

What is linear tiff data. What does it record?  (answer)

What are the differences in perception of color by males and females?  (answer)

Does the color of glass effect the index of refraction?  (answer)

Why do colors abosorb and/or reflect heat?  (answer)

What trends are typical when Munsell testing a group of people? Are there effects due to age, gender, education, or ethnicity?  (answer)

Why doesn't Pointer's gamut (CR&A, 1980) fully cover all real points in Munsell system as defined by real.dat?  (answer)

I heard that HDMI for HDTV's can have billions of colors but I also heard that our eyes can only see around 10 million colors. Does this mean all that extra color doesnt matter or will it seem clearer in some way?  (answer)

What color do most people answer when asked to name a color quickly?  (answer)

How can I get spectral reflectance information about Color-Aid samples?  (answer)

Is there any standard by which Munsell colors are called "light" or "dark" or are those terms that are too subjective so that they don't get used?  (answer)

Do you know of any freely available color matching software?  (answer)

sRGB has a gamma of 2.2. Why do the equations have an exponent of 2.4?  (answer)

Can you comment on how does the following colors affect human psychology when considered in relation to fashion designing: red, yellow, blue, green, orange, violet, brown, pink, white, black, grey?  (answer)

Are there any filters that can be placed over the eyes to make a substance, which is invisible to the naked eye, visible through the filter? Can you give an example?  (answer)

Can you provide me with a formula for RGB values given Munsell coordinates?  (answer)

Is there a range of Munsell or L*C*h coordinates that would describe browns?  (answer)

With all things being equal, is there any reason to see an increase in black dot gain simply by changing the print sequence from CMYK to KCMY?  (answer)

What is the ideal working space for digital painting in Photoshop and painter is. I tried using Adobe RGB but my reference images look so saturated.  (answer)

What color is best to paint a room with hardwood floors to enhance productiivity?  (answer)

Is there a guideline, perhaps application-based, for the number of patches needed to make adequate ICC profiles for printer output? Is there an upper limit on the number of patches beyond which more patches do not necessarily improve the ICC profile?  (answer)

I am looking for products to protect my eyes from UV-C light (254 nm). What substances are opaque or reflect to UV-C light? How harmful is UV-C light to human skin and eyes? Can you suggest any protective measures I should take?  (answer)

hat is the correlation between Hunter whiteness (L, a , b) and CIE whiteness (L*, a*, b*)? Can I relate them mathematically?  (answer)

I have a Minolta 2600d portable spectrophotometer. Can you tell me the best way to measure the fluorescence of teeth in vivo? Also, can I use the 2600d to measure the opalescence of both natural teeth and dental materials?  (answer)

Is there a certain color that has been proven to be least tiring to the eye on web page backgrounds?  (answer)

What are the calculations used to convert spectrophotometric spectral data to density, CIE XYZ, and RGB variables/values?  (answer)

Why can't humans see colors that fall in the UV or IR part of the electromagnetic spectrum?  (answer)

Could you please tell me the equivalent Federal No. (Std 595) for Munsell No. 2.1 YR 5.6/16 (Orange)?  (answer)

How can I convert NCS color mode to RGB mode in Photoshop?  (answer)

Can you explain how detergents would cause color fading?  (answer)

Do HSV and HSI refer to the same model? If not, what is the difference?  (answer)

How often should color vision testing be assessed if the ability to see colors is important in one's occupation?  (answer)

I would like to make a children's computer program emulating colour mixing of paints. Since coputers generally use the RGB colour model, I don�t know how to achieve this. Can you help?  (answer)

Can chromatic discrimination change over time or can it improve through practice?  (answer)

Any correlation between age and chromatic discrimination ability?  (answer)

Do any illnesses/physical characteristics/disabilities impact one's chromatic discrimination ability?  (answer)

How can a color display with three monochromatic lasers produce a finely rendered colorspace, with what seem like the appropriate pastels and everything?  (answer)

What are the different textures of colour?  (answer)

How can I convert CIELCH to CIE 1931 x,y coordinates?  (answer)

What is the utility of converting tristimulus values to L*a*b* values?  (answer)

Can my company's color references be accurately reproduced 10 years from now based on the tristimulus values we maintain ?  (answer)

How do the eye and the brain work together to create the chromatic adaptation 'illusion' effect with colours? Also, why does looking at certain stimulus for certain lengths of time effect the time span of the adaptation?  (answer)

What makes wet grass greener than dry grass? A scientific explanation of more than just refractive index would be much appreciated.  (answer)

What does the ratio b/a give or mean? Here a is negative and b positive.  (answer)

Can you provide list of non toxic pigments that are insoluble in water measuring about 1 micron particle diameter?  (answer)

I am preparing a 3 band fluorecent lamp powder recipe for color point x=0.312, y=0.336, Ra= 82,SDCM

Can you help me transfer color temperature to 1931 CIE xy-coordinates?  (answer)

I am shopping for a new motorcycle helmet and want to know the color's that would keep my head cooler in the sun. Where do colors such as grey or silver fit in as far as reflecting light/heat and staying cooler?  (answer)

Is there any research on changing the colors of a light to improve a surgeons abilility to see in different surgical enviroments? Can you improve their contrast sensitivity like skiers do with colored lenses.  (answer)

How do I assign a RAL number to a standard color used by my company?  (answer)

I'm measuring several 3000K white lamps. I'd like to know the color variation of these lamps. Is there any other way to measure color variation of a population of lamps, aside from standard deviation and MacAdam ellipse?  (answer)

I require formulation for a Paint that absorbs magnetic rays or RF energy used by RADAR and do not reflect back.  (answer)

Is it possible for a liquid subtance to appear clear or colorless when placed on a white piece of paper with the naked eye, but will appear a unique color when seen through a filter?  (answer)

I am interested in obtaining a very accurate spectral match of my color sample. Some of the color matching systems I have used in various paint stores do a pretty good job of matching the color but not necessarily the spectrum of my sample.  (answer)

Can you explain which coloured dyes change colour or fade and why when used as a gamma radiation dose indicator?  (answer)

What is multispectral image?  (answer)

What is the problem if a person sees both gold and silver as silver? This person also has red-green defects.  (answer)

What is the top that is black and white and makes pale colors when spun?  (answer)

I would like to perform the Farnsworth-Munsell 100 hue test on my monitor. Will this work? Can I have the values of each colour caps to form the colours?  (answer)

I am creating a colorant database for my matching software. How do I reduce the bronzing of Pth Blue at high concentrations?  (answer)

Which colored paper reflects more light?  (answer)

The color of an object depends on the reflection and the absorbtion of light. How?  (answer)

What are good books to get detailed information on both the Munsell and CIE systems? I'm an artist and have a general education of both systems but would like to know indepth knowledge of each, including the math and reasoning behind the constructions of each system.  (answer)

I am building a fiber glass airplane. The kit mfg says paint it any color you want as long as its white due to heat build up in the sun. Any idea of how far off-white I can get? How can I calculate the increase in heat absorbtion if I go a little blue or yellow off of white?  (answer)

Is there a specific color that could be called Munsell green? What is its Munsell designation? I understand this color is commonly used at places like university campuses for exterior electrical equipment enclosures.  (answer)

How is the location of an illuminant on the Planckian Locus and R-G Axes related to colour vision tests?  (answer)

What is the "straight line rule" when referring to the CIE 1931 Chromaticity Diagram?  (answer)

Which RGB values or others make color that is visible only under ultraviolet ray on the white paper?  (answer)

If one measures same color on various spectrophotometers the spectral profile is the same,but there are differences of 2-3 % in reflectance. Can you explain why? Which is the most correct reading?  (answer)

Can I use BCRA standard tile for calibration of spectrometer? Where can I buy it?  (answer)

What are the advantages and disadvanatges of chromaticity diagrams?  (answer)

Can you please define "dominant wavelength" and "wavelength of maximum absorbance"? Which should be used in the calculation of strength?  (answer)

I am writing a story about colour for children. Can you help explain (in simple terms) how a rainbow works and how the mixing of just a few colours in printing pictures in papers works?  (answer)

Would you recommend a source for standards tile for calibration of spectometer?  (answer)

How long does it take to perceive color? Are some colors perceived more quickly than others?  (answer)

I have an RGB digital SLR camera. Is it possible to find relationship between the camera output and the spectral reflectance of objects?  (answer)

How can I determine color names corresponding to hex color values?  (answer)

What is the meaning of NET profiler of a color spectrophotometer?  (answer)

When I measure delta L on low-gloss (matte finish) parts, I notice more variation between measurments than with higher gloss parts. Is there a scientific reason for this? Does the gloss play a roll?  (answer)

How can I extract a specified color from an RGB image using Matlab?  (answer)

How does one go about using use color measurements to determine the concentrations of colorants/dyes in aqueous solutions?  (answer)

I evaluate llighting systems by measuring u'v' with a spectroradiometer. How can I calculate deltaE color difference from this data?  (answer)

How is the Light Reflectivity Value (LRV) measured? Why do building codes require a certain percentage of LRV in the materials used?  (answer)

Do people with light colored eyes have better night vision than people with dark colored eyes?  (answer)

Do you know of a color/temperature chart showing various colors and their related heat reflection/absorption properties?  (answer)

What sorts of jobs would a color scientist do?  (answer)

What is the relationship between the CIELAB a*-b* opponent axes and the perceptual unique hues?  (answer)

When the 3 hands on a spinning toy (which are 3 different sizes, long, medium and short) spin around really fast, they leave 3 "trails" of light in concentric circles. Why do we see 3 complete circles of light all the time?  (answer)

Why do colors fade in the sun? is it the heat or the light?  (answer)

Do humans have a natural affinity for certain sorts of colors more than others as compared to other creatures?  (answer)

Do insects that have UV sensitivity in their visual system see the UV portion of the spectrum as "color"?  (answer)

Is color limited to the interaction of light with an object and our eyes?  (answer)

If no light is falling on an object, does it still technically have a "color"?  (answer)

How does a color TVthere is a great website describing how TV works at

How can I know the spectral sensitivity of a common CCD camera?  (answer)

Does the color green inspire thought?  (answer)

Do objects that are the same color have the same chemicals (elements) present? For example if I looked at the chemicals in red paint would I find the same ones in a red flower?  (answer)

How I can mathematically convert from CIELAB (D65,10�) to XYZ (D65,2�) or RGB?  (answer)

How do the colors you wear affect your appearance? What colors make you look certain ways?  (answer)

What is an easy way to create a color scheme using an elliptical path and a Munsell conversion program?  (answer)

Is the temperature the same in shadow under a dark colored fabric awning as under a a light colored awning?  (answer)

Sailors know from experience that darker colored fabrics last longer in full-sun exposure than white or very light colored fabrics. I am specifically referring to Sunbrella bimini and sail cover fabrics. Why?  (answer)

How do grey scale images differ from color (RGB) images?  (answer)

How can I match a paint color to Munsell N8?  (answer)

I'm looking for a Circular Spherical Vision Spectro Colorimeter for analyzing luminance and other parameters (axis etc...) of reflective materials in different colors for road construction. Can you help?  (answer)

Is there a source for a neutral gray paint designed to be used on floors and/or walls in a TV broadcast studio?  (answer)

I would like to find pigments with relatively narrow spectral aborption bands. The goal is to create paint which offsets the peak emission lines of different artifical light sources. Can you help?  (answer)

As an Interior Design student I know that paint manufacturers, geologists, anthropologists, and color designers use the Munsell system of color notation. What other industries currently his system to code their color? Automobile industry? Textile Industry?  (answer)

Why do we recognize uniqueness only for four colors, blue, yellow, green, and red? Is there any color map of unique hues in a visual system?  (answer)

How do we see metallic colors like gold and silver?  (answer)

Why is a red Popsicle red?  (answer)

What is the difference between value and chroma? If I add black or white to a color I am changing its value. How do I change its chroma?  (answer)

I measure pigments from bird egg shells with a spectrophotometer CM-2600d, should I work with 100%UV or 0%UV? What about pigments from bills and legs of birds?  (answer)

Out of blue, green or peach, which color is more likely to attract flies or insects and why?  (answer)

What effect does light have on white paper: does it reflect or transmit?  (answer)

What is chromatic textile? What properties do this textile have?  (answer)

How do I compute the correlated color temperature of an Lab/Luv color coordinate?  (answer)

I'm trying to understand whether there is an optical/physical basis for this "chameleon effect" (the ability of the materials to blend with surrounding tooth structures to create naturally appearing restorations) and whether there may be way to measure it.  (answer)

I'm looking for the paint formulation for the official colors of West Virginia University. The Pantone colors are either: A) PMS 873 metallic gold and PMS 295 Navy Blue or B) PMS 124 Gold and PMS 286 Blue. Can you help?  (answer)

In your opinion what pantone color best defines TEAL?  (answer)

Can you help me calculate the color difference between my Macbeth Colorchecker and its image after capture and display on an LCD monitor?  (answer)

I would like to purchase a grey scale color variation kit for comparing the change in color wash for Denims and Textiles. Can you recommend a source for this kit?  (answer)

Why does eye (iris) color appear to fade with old age? Is it because of the yellowing of the lens?  (answer)

Where can I find a tabulation of all pairs of distict spectral monochromatic lights that are perceived as achromatic?  (answer)

At our paint-supply company we need to match a color to existing color on a clients' wall. Is there a portable instrument we can use to determine the required mix to match the exisitng paint?  (answer)

How can I know the tricolor chromaticity coordinate of a common CCD camera?  (answer)

How does color affect our vision?  (answer)

How do I calculate the chromaticity coordinates of a single wavelength of light?  (answer)

What factors affect the intensity of color?  (answer)

What do I tell the paint store to mix in order to get a color that best matches a wavelength (5040 Angstroms)?  (answer)

Do different people see the same color in different shades? Why?  (answer)

How does one resolve the concepts of the 'scientific' (linear) color frequency model and the 'artistic' (circular) color wheel model in regards to color perception?  (answer)

I have a thin PET film that is colored with dyes. I am suprised by the amount of dye required to match the opacity of the current film. Would you say that dyes are more linear than conventional pigments are when referring to thickness and saturation?  (answer)

Do you have a table of NCS color code corresponding to RAL color code?  (answer)

What does RAL stand for?  (answer)

I am a member of an internet forum dedicated to the Rubik's cube. What is the set of 6 colors (including black/white) that human eye is best able to discriminate?  (answer)

What is the equation for plot a MacAdam ellipse? Also, what steps are the Macadam ellipses on the standard x,y chart and what do these "steps" mean?  (answer)

I am a competitive rifle shooter. Are there any colored filters to place in my rifle sight that would help to reduce eye fatigue or even simply aid in aligning things?  (answer)

What is the best method to measure the opaque black color of a plasic material?  (answer)

What distance can humans still distinguish between different colors?  (answer)

What wavelength out of red, green, blue and full spectrum would purple cabbage reflect, and what would it absorb?  (answer)

Is black paint recommend for a boy's bedroom?  (answer)

What's the RGB composition of RAL 7005 & RAL 1021?  (answer)

How can I measure the LRV value of something. Or can I convert CIELAB data into an LRV value?  (answer)

What material has the most uniform reflectance spectra, including visible, IR, and UV?  (answer)

Why are common soccer balls black and white?  (answer)

Can you help me convert between Pantone and RAL colors?  (answer)

Do clear objects reflect or absorb heat?  (answer)

Is there a simple formula to take numbers obtained by matching paint samples to the 1929 Munsell book and convert them to the numbers that would be obtained using the current Munsell book?  (answer)

Is it possible to make a color that is not visible to the human eye?  (answer)

Do age and gender matter when seeing color?  (answer)

I need a color swatch for 10YR 9/1, do you have this?  (answer)

We are trying to measure color reproduction for digital cameras using the Macbeth ColorChecker. We image the Color Checker under various illuminants. Is there a better metric to calculate the color reproduction than ΔE?  (answer)

I am trying to image a white fabric bag using a light source inside of the bag. Are there any wavelengths of light that would be most appropriate? That is, which wavelengths might be absorbed by a white acrylic fabric?  (answer)

What colour paint dries the fastest?  (answer)

What hue can the human eye dicern the most shades of?  (answer)

What does the color blue mean?  (answer)

When reading a violet, what does the Δa and Δb values represent? Example is the Δa dirty/clean or red/blue?  (answer)

In literature about discoloration of wood (furniture or parquet floors), UV-light is mentioned as the cause for the discoloration. But doesn't the glass window act as a UV-filter? So is the discoloration caused by visible light instead of UV-light?  (answer)

How I can find the formulation of paint after coating?  (answer)

I am wanting to know how broad the primaries were for the 1931 color matching experiment. Were they monochromatic, as in a laser? If not, what was the spectral half width at half max for each of the colors?  (answer)

Does the color of an ice cube affect the rate at which the ice cube will melt ?  (answer)

Can you tell me please what the CIELAB reading is of matte Munsell gray to be used inside color viewing cabinets for the print industry?  (answer)

I would like to measure the color intensity of various parts of birds. What instruments will I use?  (answer)

Why does some plastic yellow over time?  (answer)

Can you help me convert between candella and power wattage as measured by photodiode?  (answer)

I am trying to characterize my computer display. I have a failure of additivity. That is, the sum of the individual R, G, and B XYZ values does not equal the XYZ of white. Can you help?  (answer)

Can the brain take a 2D image (eg: a picture) and convert it to a 3D image?  (answer)

Assuming a monitor calibrated to the sRGB standard, is there a combination of available adjustments (gamma/contrast and/or saturation) that can be calculated and used to provide a better 'ballpark' display of an NTSC signal on an sRGB monitor?  (answer)

Can you tell me what color eye shadow would look the best for a given complexion?  (answer)

Can you tell me what the cmyk formula for silver is?  (answer)

Do different colors affect your eye sight different over time?  (answer)

Can one measure color through heat frequencies?  (answer)

What are the colour combinations or chemical substances that can be used to obtain jet black colour in a cotton flannel material?  (answer)

What is the real meaning of color blind?  (answer)

Did humans use chromatic adaptation long ago, for example in hunting?  (answer)

Does the color of your eyes affect your vision? Do people with blue eyes have better vision than those with green?  (answer)

What is the minimum ΔE that a human eye can detect? Which &Delta E"  (answer)

Do you know of any table of rgb value pairs that make up visual complementaries (colors that are afterimage of each other)?  (answer)

What color of construction paper fades the fastest?  (answer)

Why is blue light plus yellow light equal white light, but blue and yellow paints mix to green? Why do the color wheels from various systems use different primaries?  (answer)

When refering to "pure" colors (red, green, blue, orange) what is the corresponding notation in the Munsell system?  (answer)

What's method that appropriate for measure color of gemstone?  (answer)

How does color affect our mood?  (answer)

Which of these Munsell soil designations is the reddest: 5R 6/4, 5R 5/2, 5R 7/3, 5R 6/3?  (answer)

Can you help me explain (in simple terms for a 5 year old child) why some colors of popsicles melt faster than others?  (answer)

Can you provide the pantone equivalent to GE plastic FXM171R-GY2A360M?  (answer)

Can you help me find a cost-effective way to measure black-gray-white and all shades in between. My son is doing an science experiment to determine how well erasers work.  (answer)

Can you help me create the color green that is exactly in the middle of the green color spectrum using the RGB values of my display?  (answer)

I need an example or a graph help to explain why humans cannot see colors that fall in the ultraviolet or infrared part of the electromagnetic spectrum.  (answer)

Specifications on the web given by SAE, ECE eg, mention that the colour should fall within the given boundary:
y = 0.335 (yellow boundary)
y = 0.980 - x (purple boundary)
What does this mean?  (answer)

Is there anyone who I can pay to convert 12 colors with LCh values into Lab or Munsell values?  (answer)

In my prepress company we have to convert fabric samples by eye in to CMYK values. This is time consuming. Is there a software hardware combo that can read a piece of fabric and give the best cmyk values in a specific profile?  (answer)

How does the eye see colors that are moving very rapidly? (eg: a spinning color wheel)  (answer)

Why does light create color?  (answer)

What is neutral grey colour shade and the pantone number for neutral grey in pantone formula guide solid uncoated and uncoated ?  (answer)

How can I make a colored chromaticity diagram?  (answer)

Could you recommend a good website for the glossary of color imaging terms?  (answer)

Do you know of any research into the quantity of a particular colour eg., yellow that is in a painting and whether that painting is one that gives pleasure?  (answer)

Which colour has the most easily visually discriminable levels of saturation? The literature seems to suggest blue violet as this has the most steps when white light is added in 'just noticeable' amounts - would you agree with this?  (answer)

What do the various CIE illuminant designation mean (D55, D65, etc)? How are they related to each other and to CCT?  (answer)

What colors should I use for my experiment on which colors absorb more heat? I already know I am doing black and white.  (answer)

How do colored objects reflect heat?  (answer)

Can you help me transform Lch values to Lab?  (answer)

Does the first color you see when you wake up effect your mood?  (answer)

Does the color of your car determine the temperature in the car?  (answer)

Do you think people can remember words better from colored paper or white paper?  (answer)

I would like to do a science experiment on "Will male and females chose the color that has been associated with their gender?" For example, pink for girls and blue for boys. Can you help be to create a 5th grade science experiment to test this idea?  (answer)

In literature it is mentioned that the difference between SCE and SCI color measurements gives an indication for the gloss of the surface. Which parameters are used to evaluate this: the difference between the SCI and SCE values for CIE-L, a, b or a combination?  (answer)

What would be the reason to use CIELAB, CIELCH, CMC, CIE94, and CIE2000 (all of the above together) to calculate color difference from sample to standard?  (answer)

What is the best way to test color fading in construction paper? My child is making an experiment on what color will fade the fastest when exposed to sunlight.  (answer)

What chemicals are used to create fluorescent paint?  (answer)

Can you provide the CMYK formula for ANSI Safety Green?  (answer)

Is there direct co-relation between CIE 76 and ANLAB 40 and ANLAB 50 color spaces?  (answer)

What is the primary calibration of a spectrophotometer?  (answer)

Please explain the Bradford Chrmatic adaptation transform as a physical phenomenon and provide the mathematical basis.  (answer)

Are HSL values that the Paint accessory of Windows system use recognised by CIE ?  (answer)

Is there a mathematical conversion from RGB to HTML color code?  (answer)

Can you derive CIELAB values directly by visually inspecting the reflectance curve?  (answer)

Can you explain the mechanism of UV filter in color spectrophotometer, to get universal Whiteness values on all spectros. Is it a wedge filter or an attenuator filter.  (answer)

Does the color of light affect how much snow is melted?  (answer)

Can human eyes see noise? Or, can our brain recognize what's signal and what's noise?  (answer)

I work in printing. Can you tell me what the effect of dot gain is on delta E? Also, can we get an accurate delta E measurement from a coated sheet to an uncoated sheet?  (answer)

What colors absorb more heat, when a piece of ice is sitting on the piece of paper on a hot and sunny day?  (answer)

How specifically does a magenta-dyed silver halide crystal absorb green energy? I know it has to do with wavelength ... is magenta somehow 'dovetailing' with green light to chemically interact?  (answer)

For other uses, see Lightness (disambiguation).

In colorimetry and color theory, lightness, also known as value or tone, is a representation of variation in the perception of a color or color space's brightness. It is one of the color appearance parameters of any color appearance model.

Various color models have an explicit term for this property. The Munsell color model uses the term value, while the HSL color model, HCL color space and Lab color space use the term lightness. The HSV model uses the term value a little differently: a color with a low value is nearly black, but one with a high value is the pure, fully saturated color.

In subtractive color (i.e. paints) value changes can be achieved by adding black or white to the color. However, this also reduces saturation. Chiaroscuro and Tenebrism both take advantage of dramatic contrasts of value to heighten drama in art. Artists may also employ shading, subtle manipulation of value.

Relationship to value and relative luminance[edit]

The Munsellvalue has long been used as a perceptually uniform lightness scale. A question of interest is the relationship between the Munsell value scale and the relative luminance. Aware of the Weber–Fechner law, Munsell remarked "Should we use a logarithmic curve or curve of squares?"[1] Neither option turned out to be quite correct; scientists eventually converged on a roughly cube-root curve, consistent with the Stevens' power law for brightness perception, reflecting the fact that lightness is proportional to the number of nerve impulses per nerve fiber per unit time.[2] The remainder of this section is a chronology of lightness approximations, leading to CIE LAB.

Note. – Munsell's V runs from 0 to 10, while Y typically runs from 0 to 100 (often interpreted as a percentage). Typically, the relative luminance is normalized so that the "reference white" (say, magnesium oxide) has a tristimulus value of Y = 100. Since the reflectance of magnesium oxide (MgO) relative to the perfect reflecting diffuser is 97.5%, V = 10 corresponds to Y = 100/97.5% ≈ 102.6 if MgO is used as the reference.[3]

Priest et al. provide a basic estimate of the Munsell value (with Y running from 0 to 1 in this case):[4]
Munsell, Sloan, and Godlove launch a study on the Munsell neutral value scale, considering several proposals relating the relative luminance to the Munsell value, and suggest:[5][6]
Newhall, Nickerson, and Judd prepare a report for the Optical Society of America. They suggest a quintic parabola (relating the reflectance in terms of the value):[7]
Using Table II of the O.S.A. report, Moon and Spencer express the value in terms of the relative luminance:[8]
Saunderson and Milner introduce a subtractive constant in the previous expression, for a better fit to the Munsell value.[9] Later, Jameson and Hurvich claim that this corrects for simultaneous contrast effects.[10][11]
Ladd and Pinney of Eastman Kodak are interested in the Munsell value as a perceptually uniform lightness scale for use in television. After considering one logarithmic and five power-law functions (per Stevens' power law), they relate value to reflectance by raising the reflectance to the power of 0.352:[12]
Realizing this is quite close to the cube root, they simplify it to:
Glasser et al. define the lightness as ten times the Munsell value (so that the lightness ranges from 0 to 100):[13]
Wyszecki simplifies this to:[14]
This formula approximates the Munsell value function for 1% < Y < 98% (it is not applicable for Y < 1%) and is used for the CIE 1964 color space.
CIE LAB uses the following formula:
where Yn is the CIE XYZY tristimulus value of the reference white point (the subscript n suggests "normalized") and is subject to the restriction Y/Yn > 0.01. Pauli removes this restriction by computing a linear extrapolation which maps Y/Yn = 0 to L* = 0 and is tangent to the formula above at the point at which the linear extension takes effect. First, the transition point is determined to be Y/Yn = (6/29)^3 ≈ 0.008,856, then the slope of (29/3)^3 ≈ 903.3 is computed. This gives the two-part function:[15]
The lightness is then:

At first glance, you might approximate the lightness function by a cube root, an approximation that is found in much of the technical literature. However, the linear segment near black is significant, and so the 116 and 16 coefficients. The best-fit pure power function has an exponent of about 0.42, far from 1/3.[16]

An approximately 18% grey card, having an exact reflectance of , has a lightness value of 50. It is called "mid grey" because its lightness is midway between black and white.

Other psychological effects[edit]

This subjective perception of luminance in a non-linear fashion is one thing that makes gamma compression of images worthwhile. Beside this phenomenon there are other effects involving perception of lightness. Chromacity can affect perceived lightness as described by the Helmholtz–Kohlrausch effect. Though the CIE LAB space and relatives do not account for this effect on lightness, it may be implied in the Munsell color model. Light levels may also affect perceived chromacity, as with the Purkinje effect.

See also[edit]


External links[edit]

Media related to Lightness at Wikimedia Commons

Three hues in the Munsell color model. Each color differs in value from top to bottom in equal perception steps. The right column undergoes a dramatic change in perceived color.

Observe that the lightness is 50% for a relative luminance of around 18% relative to the reference white.
  1. ^Kuehni, Rolf G. (February 2002). "The early development of the Munsell system". Color Research & Application. 27 (1): 20–27. doi:10.1002/col.10002. 
  2. ^Hunt, Robert W. G. (May 18, 1957). "Light Energy and Brightness Sensation". Nature. 179 (4568): 1026. doi:10.1038/1791026a0. 
  3. ^Valberg, Arne (2006). Light Vision Color. John Wiley and Sons. p. 200. ISBN 0470849029. 
  4. ^Priest, Irwin G.; Gibson, K.S.; McNicholas, H.J. (September 1920). "An examination of the Munsell color system. I: Spectral and total reflection and the Munsell scale of Value". Technical paper 167 (3). United States Bureau of Standards: 27. 
  5. ^Munsell, A.E.O.; Sloan, L.L.; Godlove, I.H. (November 1933). "Neutral value scales. I. Munsell neutral value scale". JOSA. 23 (11): 394–411. doi:10.1364/JOSA.23.000394. Note: This paper contains a historical survey stretching to 1760.
  6. ^Munsell, A.E.O.; Sloan, L.L.; Godlove, I.H. (December 1933). "Neutral value scales. II. A comparison of results and equations describing value scales". JOSA. 23 (12): 419–425. doi:10.1364/JOSA.23.000419. 
  7. ^Newhall, Sidney M.; Nickerson, Dorothy; Judd, Deane B (May 1943). "Final report of the O.S.A. subcommittee on the spacing of the Munsell colors". Journal of the Optical Society of America. 33 (7): 385–418. doi:10.1364/JOSA.33.000385. 
  8. ^Moon, Parry; Spencer, Domina Eberle (May 1943). "Metric based on the composite color stimulus". JOSA. 33 (5): 270–277. doi:10.1364/JOSA.33.000270. 
  9. ^Saunderson, Jason L.; Milner, B.I. (March 1944). "Further study of ω space". JOSA. 34 (3): 167–173. doi:10.1364/JOSA.34.000167. 
  10. ^Hurvich, Leo M.; Jameson, Dorothea (November 1957). "An Opponent-Process Theory of Color Vision". Psychological Review. 64 (6): 384–404. doi:10.1037/h0041403. PMID 13505974. 
  11. ^Jameson, Dorothea; Leo M. Hurvich (May 1964). "Theory of brightness and color contrast in human vision". Vision Research. 4 (1-2): 135–154. doi:10.1016/0042-6989(64)90037-9. PMID 5888593. 
  12. ^Ladd, J.H.; Pinney, J.E. (September 1955). "Empirical relationships with the Munsell Value scale". Proceedings of the Institute of Radio Engineers. 43 (9): 1137. doi:10.1109/JRPROC.1955.277892. 
  13. ^Glasser, L.G.; A.H. McKinney; C.D. Reilly; P.D. Schnelle (October 1958). "Cube-root color coordinate system". JOSA. 48 (10): 736–740. doi:10.1364/JOSA.48.000736. 
  14. ^Wyszecki, Günther (November 1963). "Proposal for a New Color-Difference Formula". JOSA. 53 (11): 1318–1319. doi:10.1364/JOSA.53.001318. Note: The asterisks are not used in the paper.
  15. ^Pauli, Hartmut K.A. (1976). "Proposed extension of the CIE recommendation on "Uniform color spaces, color spaces, and color-difference equations, and metric color terms"". JOSA. 66 (8): 866–867. doi:10.1364/JOSA.66.000866. 
  16. ^Poynton, Charles; Funt, Brian (Feb 2014). "Perceptual uniformity in digital image representation and display". Color Research and Application. 39 (1): 6–15. doi:10.1002/col.21768. 


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