New answers tagged color-spaces
There isn't a formula, but there are some well-tested design guidelines. Two colors that have similar (greyscale) tonal values will not have sufficient contrast to be easily read. Colors which are opposite one another on the color wheel (complementary colors such as red and green, to take your example) tend to "glare" when placed in immediate proximity, so ...
Hello there is another question on this website similar to this one with more information in case you were having issues like me: http://graphicdesign.stackexchange.com/a/29301/27134 The main key is to "Expand" the image and use the Direct Selection Tool (A).
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