# How to find four equally contrasting colours that are appealing to the eye?

I have a plot for a scientific argument I'm trying to make. There are four colours that should be (roughly) equally contrasting with two others. ie, if the colours are A-D, then A and B should be roughly as contrasting as B and C, and C-D, and D-A. A-C should be about the same as B-D...

Basically for starters I chose a bright red, green, yellow, and blue. This makes my point well, but looks pretty bad. I find it quite harsh. Do you have any ideas for how to improve this? My thought, not yet implemented, is to do black, gold, white, and purple.

• The point about the contrast was that they can't just be four tones of the same colour, cause then A-D will be a lot more than A-B, B-C, or C-D. Commented Feb 21, 2016 at 9:09

The problem with your red, green, blue, yellow set is that is all the colors. You can make every color by mixing those. A more limited color set will likely look better.

Red and green are not directly contrasting colors. You would want red and cyan. Other contrasts are blue and yellow, or green and magenta.

But you are talking about pleasing the eye. That is art, not science. So you should consider just trying a few color combinations until your eye is pleased and your scientific point is still expressed. If you create 4 squares in a grid in a graphics tool (on the background color you will be using) and work with various colors and tones until you have a set that is both distinctive from each other yet pleasing to look at together that will likely get you the best result.

There are online tools specifically for designing color sets.

10 Sites to Play with Colors

• uh... I disagree with your statements in your first two paragraphs. How would you 'mix' magenta from those four? And red-green is a contrast that has been used many, many times over. Yes, according to some colour modles like RGB and HSB they aren't complimentary, but it is a good contrast nonetheless. Commented Feb 23, 2016 at 15:45

You can use a basic color wheel to see which colors contrast and choose the pairs you like best.

Or you can use Palletton to choose four contrasting colors. Just move the outer pins around the color wheel. They will always stay 90 degrees apart, thus giving you contrasting colors. Click on Tables/Export on the bottom right of the site to see a list of the colors in RGB and Hex values.

I'm not sure your diagram has the correct colors next to each other. From what I read about appealing colors, Red and Green next to one-another is also hard on the eye.

The concept is called Chromostereopsis:

https://en.wikipedia.org/wiki/Chromostereopsis

And here's a quote from another site on the concept (http://www.eye-therapy.com/Color/Chromostereopsis/):

In 1885, W. Einthoven was the first scientist to study the chromostereopic effect. There is a difference between the visual and optical axes. Therefore, light from the fovea will hit the corneal surface at an angle, causing a prism effect. Blue, with its shorter wavelengths, is refracted more than red with its longer wavelengths. Blue light is focused toward the nose, making it appear farther than red which is focused toward the temple.