carol.gimp.org

I have been reading Computer Graphics: Principles and Practice by Foley, vanDam, Feiner and Hughes; Chapter 13, and it starts out rather poetically:

"When a surface that reflects only pure blue light is illuminated with pure red light, it appears black. Similarly, a pure green light viewed through glass that transmits only pure red will also appear black."

Here is the interesting part about greenish.

(from the section Interactive Specification of Color)

"The basic choices are to use English-language names, to specify the numeric coordinates of the color in a color space (either by typing or with slider dials), or to interact directly with a visual representation of the color space. Naming is in general unsatisfactory because it is ambiguous and subjective ("a light naby blue with a touch of green"), and it is also the antithesis of graphic interaction. On the other hand, [BERK82] describes CNS, a fairly well-defined color-naming scheme that uses terms such as "greenish-yellow", "green-yellow", and "yellow-green" to distinguish three hues between green and yellow. In an experiment, users of CNS were able to specify colors more precisely than were users wou entered numeric coordinates in either RGB or HSV space. "