Allowing to chose proportions of colors could be even better.
Hypothetical example: Lets suppose that I'm a policeman. How much percentage of black, white and red is in a classical svastika?. Then browse the dark web for finding all webs that contain this particular white, black and red in such combination
Other possibilities: I want to know if my [bank/company/chess club] web is being cloned and used to criminal purposes without my knowledge. My logo contains magenta, lime green and burnt orange. Find me webs with this combination that aren't in a list of official webs from my company. Even better, check it at real time on email to spot scammers impersonating me on real time.
The applications are endless: I want to detect webs that sell fake clones of my products; or find photos of pills of a particular shade of blue. Or don't show me webs with a high content in warm tones associated with porno images...
Yep, that could be a really revolutionary startup.