Transmitted colour of a solution

[Moogie]

Hi

The colour of a solution is the wavelength of the light transmitted through it which is white light minus the absorbed colour.

If a solution absorbs light of wavelength 630nm, what colour is it? 630nm is red /orange light. If you look on a colour wheel the complementary colour of this is blue but is there a formula or more precise way to work this out?

thanks

[JDługosz]

Try reading this (http://www.handprint.com/HP/WCL/wcolor.html). In general, you sum the responses of the 3 cones for each frequency, and the result ratio determines the human color perception. Subtracting out one might be simpler than adding everything else, but use the CIE "horseshoe" diagram (http://en.wikipedia.org/wiki/Chromaticity_diagram#The_CIE_xy_chromaticity_diagr am_and_the_CIE_xyY_color_space) rather than a simple color wheel. Draw a line from the chosen white point (there are a couple to choose from!) to the frequency written along the edge, and go backwards from the white point, away from the frequency's point on the edge.

--John