At what illuminant temperature are Munsell neutrals (N6, N7, etc.) designed to be. How can I convert NCS color mode to RGB mode in Photoshop? Munsell conversion software free download - Munsell DG, Munsell Viewer, Conversion, and many more programs.
I am trying to convert a HSB Color to RGB. The way I am doing that is System.Windows.Media.Color winColor = value;System.Drawing.Color drawColor = System.Drawing.Color.FromArgb(winColor.R, winColor.G, winColor.B);Hue = (byte)(drawColor.GetHue.255);Saturation = (byte)(drawColor.GetSaturation.255);Luminosity = (byte)(drawColor.GetBrightness.255);I find that when I have FF0000, it will be converted to H = 0, S = 255, L = 127 which converts to RGB FF0E0E. I think Luminosity should be 120? Or am I getting the whole HSB thing wrong?
When I look at the color picker in Photoshop, Hue is 0-360 degrees, Saturation, Luminosity is 0-100%. I am having HSB values ranging from 0 - 255, am I doing it wrong?
I'm looking at at document that describes the standard colors used in dentistry to describe the color of a tooth. They quote hue, value, chroma values, and indicate they are from the 1905 Munsell description of color:The system of colour notationdeveloped by A. Munsell in 1905identifies colour in terms of threeattributes: HUE, VALUE (Brightness)and CHROMA (saturation) HUE (H): Munsell defined hue as thequality by which we distinguish onecolour from another. He selected fiveprinciple colours: red, yellow, green,blue, and purple; and fiveintermediate colours: yellow-red,green-yellow, blue-green, purple-blue,and red-purple. These were placedaround a colour circle at equal pointsand the colours in between thesepoints are a mixture of the two, infavour of the nearer point/colour (seeFig 1.).VALUE (V): This notation indicates thelightness or darkness of a colour inrelation to a neutral grey scale,which extends from absolute black(value symbol 0) to absolute white(value symbol 10).
This is essentiallyhow ‘bright’ the colour is.CHROMA (C): This indicates the degreeof divergence of a given hue from aneutral grey of the same value. Thescale of chroma extends from 0 for aneutral grey to 10, 12, 14 or farther,depending upon the strength(saturation) of the sample to beevaluated.There are various systems forcategorising colour, the Vita systemis most commonly used in Dentistry.This uses the letters A, B, C and D tonotate the hue (colour) of the tooth.The chroma and value are bothindicated by a value from 1 to 4. A1being lighter than A4, but A4 beingmore saturated than A1. If placed inorder of value, i.e.
Brightness, theorder from brightest to darkest wouldbe:A1, B1, B2, A2, A3, D2, C1, B3, D3,D4, A3.5, B4, C2, A4, C3, C4The exact values of Hue, Value andChroma for each of the shades is shownbelow So my question is, can anyone convert Munsell HVC into RGB, HSB or HSL? Hue Value (Brightness) Chroma(Saturation) 4.5 7.80 1.72.4 7.45 2.61.3 7.40 2.91.6 7.05 3.21.6 6.70 3.15.1 7.75 1.64.3 7.50 2.22.3 7.25 3.22.4 7.00 3.24.3 7.30 1.62.8 6.90 2.32.6 6.70 2.31.6 6.30 2.93.0 7.35 1.81.8 7.10 2.33.7 7.05 2.4They say that Value(Brightness) varies from 0.10, which is fine. So i take 7.05 to mean 70.5%.But what is Hue measured in? I'm used to hue being measured in degrees (0.360). But the values i see would all be red - when they should be more yellow, or brown.Finally, it says that Choma/Saturation can range from 0.10.or even higher - which makes it sound like an arbitrary scale.So can anyone convert Munsell HVC to HSB or HSL, or better yet, RGB? The hue specification you've given here is incomplete (4.5 should be 4.5Y etc).
Since the link is dead, if anyone is interested, the specs are still alive here:The only free utility for Munsell conversion I could find was this:Very old as you can see, but seems to work well. Current programs that can do this are not free:. (this one has a free 14 day trial)The current holders of the Munsell products are, they probably have some conversion solutions as well.Further, note that the link you supplied includes definitions for the same colors in other color coordinates - namely Yxy and CIE l ab. Both can be freely converted online at or offline with this.
It is rather involved. The short answer is, converting Munsell codes into RGB involves interpolation of empirical data in 3D that is highly non-linear.
The only data set that is publicly available was collected in the 1930's. Free or inexpensive programs that I have found on the net have proved to be flawed. I wrote my own.
But I am jumping ahead. Let's start with the basics.Munsell codes are different in kind than those other codes, xyY, Lab, and RGB. Munsell notation describes the color of an object - what people experience when they view the object. (Isaac Newton was the first to realize that color is in the eye of the beholder.) Munsell conducted extensive experiments with human subjects and ingenious devices.The other codes, i.e. XyY, L ab., and RGB, describe light that has bounced off an object and passed through a convolultion with a rather simple mathematical model of a human eye. Some google-terms are 'illuminant,' 'tri-stimulus,' and 'CIE standard observer.' Munsell describes the colors of objects as they are perceived under a wide variety of illuminants.
Another google-term is 'chromatic adaptation.' Chromatic adaptation in the brain is automatic if the lighting is not too weird. It is really quite remarkable.
Take a piece of typing paper outside under a blue sky. The paper looks white. Take it indoors and look at it under incandescent (yellowish) lights. It still looks white! Munsell tapped into that astonishing processing power empirically.
Munsell codes also preserve perceived hue at different chromas. A sky-blue and a powder-blue that Munsell assigns the same hue notation, e.g. 5RP, will appear to the typical human with normal eyesight to be the same hue. More on that in the footnote.CIE xyY, L ab., and RGB mean nothing unless an illuminant is specified. Chromatic adaptation for illuminants in the mathematical model is computationally difficult. (Rough but simple approximations can be done using the 'Bradford matrices.' ) The RGB that we use is by default 'sRGB,' which specifies an illuminant called D65.
D65 is something like a cloudless day at noon. The Lab numbers listed by the OP are probably relative to D50, which is more like afternoon or morning light.
The xyY numbers might be relative to D50, or they might be relative to an old standard called C. I am not going to check. C was the light from a standard lighting fixture that was relatively inexpensive to build in the 1930's. It is obsolete. But C plays a key role in the answer to the question.In the 1930's, color scientists were developing the mathematical models. One of the things they did was to take a standard Munsell Book of Color, shine illuminant-C light on the colored chips in the book, and record the data in xyY format.
That data-set, called the 'Munsell Renotation Data,' is the only one that is freely available. Others surely exist, but they are closely held secrets.Good news though. The data set works good. The Munsell authority today is a company called Gretag Macbeth. I imagine they have voluminous data related to the color-chips they sell.
The only numbers I know of that they publish are the D50 Lab and D65 sRGB numbers for a small set of colors on their cards. I wrote an interpolator based on the old renotation data. It agrees with the numbers for the Color Checker card almost exactly. I regret to inform that so far I have only written code for the conversion that goes the opposite direction from what the OP requested (a year ago, as I type this). It goes from sRGB to Munsell. I click on an image, and the program displays the sRGB and Munsell notations for the area clicked upon.
I use it for oil painting.Footnote: CIE has a standard that is analogous to Munsell. It is called LCh subscripted with a,b. It is L ab. in polar coordinates.
The hues are in degrees. Chroma numbers are approximately 5 times the C in Munsell HVC. LCh has its problems though. If you have ever used a photo editor to pump up the vividness of the sky, only to see the blue turn to purple, the program was probably using LCh. When I started writing my program, I was unaware that Bruce Lindloom had done work that parallels what I was doing.
Was invaluable to me as I finished the project. He designed a space he calls UPLab, which is LCh straightened out to align with Munsell. I had already re-invented LCh and (essentially) UPLab before I discovered Mr. Linbloom's site, but his knowledge of the subject far exceeds mine. Munsell Renotation System to sRGB Colourspace Conversion, our open source Python colour science package allows to perform that conversion. I'm late to the party, but I found another resource that may be useful on this topic.Someone at the 'Munsell Color Science Laboratory' dug up some 1943 data from Munsell, all based on 1930s Munsell research:The page refers to an Excel spreadsheet with the 'real colors only' subset of the data that falls within the 'Macadam limit', which appears to mean the gamut of colors that can actually appear on reflective surfaces. The spreadsheet link doesn't work, however, but on a hunch I guessed that it left out one level of the directory tree.
I tried the URL - and it worked. (I wouldn't be surprised if the owner of the site eventually notices it, and fixes the link, which is likely to break my link.)I messed with that spreadsheet a little to get it to generate HTML to show me the RGB colors, and added these cells to the spreadsheet:.
Despite this old post, to update Steve's answer, here are 'corrected' links to RIT's repositories of Munsell data:And a direct link to spreadsheet of the sRGB converted values of the 'real' Munsell colors:It's a spreadsheet which includes a conversion from Munsell HVC notation to xyY, then to XYZC, then converted to D65 illuminant, then to floating point sRGB, then quantized to 8bit sRGB values (which they call dRGB).As for the OP's question: sRGB is (obviously) an RGB additive color model. But the differences to other color models such as subtractive CMYK are complex enough that a 'simple' algorithm won't handle the conversion — while color model transformations can be approximated with a matrix, more often a LUT (Look Up Table) is preferred, such as a LUT in an ICC profile or a 3D LUT as used in film production.