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Re: physical colors and Mathematica colors

• To: mathgroup at smc.vnet.net
• Subject: [mg26416] Re: physical colors and Mathematica colors
• From: malakm at rpi.edu (Michael Jay Malak)
• Date: Wed, 20 Dec 2000 00:21:39 -0500 (EST)
• Organization: Rensselaer Polytechnic Institute, Troy NY, USA
• References: <91f7u4$55k@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

PNichols at cornell-iowa.edu writes:

>Dear Group,

>I am working on a package for which I need a function which takes a
>wavelength of light (in nanometers, for example) and returns an RGBColor
>specification.  Has anyone made such a function for Mathematica?

>Of course, it is not essential that the result be RGBColor; any other
>standard computer-graphics color model would do the job (HSB, HLS, CMY,
>CMYK, etc.), because the conversions are standard.  It's only the conversion
>between one of these and physical wavelengths which I don't know.

>I understand that human color perception is a complicated matter, and so is
>rendering of color on computer display devices.  (The brightness dimension
>is perhaps the most obvious ambiguity.)  It's probably nonsense  to ask for
>a "perfect" correspondence between wavelength and RGB.  But is there a
>"standard" mapping?  Or one that you think is "pretty good"?

>I shall be grateful for even the smallest suggestions.


>Preston Nichols
>Visiting Assistant Professor of Mathematics
>Cornell College
> 

Preston,

There are a number of references listed at
http://www.physics.sfasu.edu/astro/color.html
although I think that none of them is written in Mathematica.

There is actually a well-defined correspondence between wavelength and
RGB (see http://www.physics.sfasu.edu/astro/color/cie_xyz1964.html),
although I'm not sure how brightness figures in.  Of course,
translating it to the screen also involves issues like gamma
correction.

Mike
-- 
Michael Malak                |  1. All syllogisms have three parts.
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