The Image Conscious art publishing web site lacked a color search feature, rather an obvious omission. Scanning the competition showed some ok and some less-ok ways to go about it; oddly there didn’t seem to be any viable plugins to entirely cover our needs.
I spent a lot of time playing with image manipulation libraries, analyzing images for color content and choosing a color model (HSL for the win). After setting up a front-end color picker, I then set some range tolerances for the query to bring back decent sets of results.
See the result on the live Image Conscious web site.