Re: physical colors and Mathematica colors

*To*: mathgroup at smc.vnet.net*Subject*: [mg26394] Re: physical colors and Mathematica colors*From*: "Borut L" <justmyname at email.si>*Date*: Wed, 20 Dec 2000 00:21:23 -0500 (EST)*References*: <91f7u4$55k@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

> 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? > > 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"? Hi, I don't think that will be much help to you. I hope at least a bit. Anyway, I guess linear mapping from wavelength to hue percentage domain is a good first order approximation. hueValue[lambda_] := Fit[{{380, 0.8}, {750, 0}}, {1, lambda}, lambda] Where 380nm corresponds to violet and 750nm to red, and correspondig hue values are 0.8 and 0. I don't know if binaries are permitted in this newsgroup (if not, they should be!), but I even made an image collaged from 'true' (above) specter and Mathematica Hue (below) linear specter. [no binaries - contact the author to get this - moderator] Usage of Hue[h] is equivalent to Hue[h,1,1] where saturation and brightness are taken to be 1, i.e. 100%. Well, bye Borut Levart a physics student