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Thread: Munsel color scheme
August 3rd, 2009 #1
Munsel color scheme
Hi guys, I am trying to make a tool - color viewer of some kind - where I would like to display hues in the Munsel style(and some other properties of color too). What I need to do is to find proper values of hue angles for the basic 20 Munsel hues.
In case I have my monitor calibrated, asuming that R G and B components are ideal red green and blue parts from the visual spectrum (more or less), what angles in terms of H from HSB color space, are closest to their real life eqvivalents in Munsel color scheme. I assume the ones closest in chroma(saturation on monitor) and I assume that with changing lighness and chroma the hues remains the same (more or less), but within 5 angle steps of a hue scale. So that when I point at some color on my calibrated monitor I could say that it is 5R and not 10R or 10YR.
Any link, comment is appreciated
Thank you in advance
Hide this ad by registering as a memberAugust 3rd, 2009 #2
Munsell doesn't translate directly to monitor colors since Munsell refers to the surface colors of things and monitors emit light- and that light varies quite a bit from monitor to monitor. It's not just as simple as calibrating your monitor. The math is pretty hairy and the results vary depending on which Munsell data you use, the illuminant you decide to mathematically "view" the colors with, and the specific RGB space that you are converting to. It doesn't always look so great either.
My advice would be to carry the concepts of Munsell over to digital, but skip converting the actual numbers. On the monitor:
- use H from HSB in place of Munsell Hue
- use L from Lab in place of Munsell Value
- use Saturation from HSB in place of Munsell Chroma
If you want to approximate the Munsell hues, use steps of 72 (360/5), 36 (360/10), or 18 (360/20) etc.
You might be interested in the Photoshop swatch generator a few of us here put together which generates photoshop swatches based on even steps of the color components listed above. It's fairly customizable as to the hues & chromas it will produce. You can find it in this thread (post #11 has the most recent version):
If you'd really like some actual Munsell values converted to RGB, there's an image in that thread of the results of an actual Munsell conversion I did a while back. Note the rather large amount of inconsistencies even within one Munsell hue value. Also note that these are the values for one particular set of Munsell data under one illuminant converted to one RGB space- not the "correct" Munsell values for a given swatch. You can find the image in this post:
August 4th, 2009 #3
Thank you very much dose for this link, plenty of usefull sources are there.
So, what I am for is to make a tool, that is able to show H S B numbers, L from Lab as well and some other informations about it and it actually works right now. The only problem is according to what data should I calibrate this tool to show proper munsel hues. I know that it's not so easy, if I would ever be able to do that in my conditions (restricting only to those musel colors within my monitor's gamut), it would be different on another monitor (though calibrated).
What I am for is pretty fair approximation, for the reason of naming of hues. Hue in degrees doesn't seem to be so great for this purpose. I like munsel system much more. Brightnes and Lightness is pretty easy to compute and show within the scale 0 - 100. But apart from Hue degrees I would like to name it semantically. If you know any better naming convention as for color hues pls let me know. For now, I know all colors on monitor are relative to each other, I wont get the real color information without outside meassurements and I don't even need it.
So when I point with mouse pointer to some pixel, I would like to see the relative hue (in HSB angle manner) and its fairly close Munsel name.
Maybe I could calibrate it to your munsel color swatches and We'll see how handy this tool could be.
CU and thank you again
August 4th, 2009 #4
Hey, I've been clicking over your swatches and with few exceptions it works. Actually I have calibrated it using swatches on this site : http://www.triplecode.com/munsell/index.html
I could fine-tune it, but some errors remains around very low saturations (but that's even because of quantization error).
I am sending the (autohotkeys's script) and exe for anybody who wants to check this out. It's very simple right now. Script listen to Win+left_mouse ('Win logo key', 'Left mouse button click') and shows 2 seconds lasting tooltip with few number : V,h,s,b. Where V is (100 - L) where L is perceptive lighness(now as simple as L = (3*r + 6*g + b) / 10). h, s and b are simply the same hue(0-360) in degrees, saturation and brightness (1 - 100) in percentage; the same as are available in PS. When you start executable, an icon appears in tray from where this script could be suspended or closed. For those who don't trust my exe there's human-readable script from which it is compiled (you can download autohotkeys and adjust/compile it yourself).
Here is the tool
PS: right now I can't get it work properly inside PS toolbars( color swatches, color picker ) where it gets different r g b values, but it works inside canvas properly.
Last edited by siiilon; August 4th, 2009 at 08:49 AM.