lets say I have a rectangle divided in two complementary colors, yellow and purple.

enter image description here

How can I calculate the percentage of surface that both colors require so that none seem to take over ? (I'm looking for a tool that would do this for me)

3 Answers 3


I don't know of any tool to do this automatically, but possibly of help is to convert the image to LAB color space, and examine histograms of the A channel and B channel. See if there are as many points to the left of the center (which represents grayscale) as to the right. If not, adjust the rectangles proportions and examine again.


Hm. This is a toughie. I would think that this would be a purely subjective call. It might help to see the context this is going to be in - is it part of a larger yellow / purple design or is it standing against a white or black (or lime green or violent orange) background? If the former, I would think that the percentage should either matcht he percentage of the background (to blend in) or be the complete opposite (to stand out).

If it's going against some other background I'd still have to see the context it's going in. Are you going to be putting text in / under / over / around it? If so, give more weight to the areas that will have text (or the text you want people to lend more importance to).

Unfortunately, I don't think there's an app that could do anything more than give you a very formulaic response, and that's kind of the opposite of aesthetic design. As of yet, they haven't come up with a robot that's capable of that kind of graphical judgement. Or love. sigh

  • This is rather a theoretical question, but I need it for a user interface with blue windows and orange buttons. Mar 14, 2011 at 23:00
  • Are you so sure that it is the opposite of aesthetic design ? So far we've been able to identify the golden ratio, the rule of thirds, the Fibonacci suite, the complimentary colors , the canons of beauty etc and we have been able to computerize them. Robots don't need to understand what they do :-) Anyway, you're saying there could be a tool that would only give me a mathematical answer ? well lets try it. I found numeral.com/cb.html & applepainter.com/Chap06 Mar 14, 2011 at 23:16
  • 1
    The canons of beauty are cultural and therefore subjective. The correct answer to your question is that no program can do any better than a reasonably astute observer. If you need more, you can write a program with an arbitrary decision tree that black-boxes it for people who are in desperate need of some form of argument from authority.
    – horatio
    Mar 15, 2011 at 16:39

How can I calculate the percentage of surface that both colors require so that [neither seems] to take over ?

This seems to be asking for a precise answer to an imprecise question. You could probably answer it for your own perception, on a screen with a given gamma for each RGB channel, with given lighting.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.