Dear Steemies, i decided to help you with some educational illustrations about colors.
The secondary and tertiary colors are created by mixing the two adjacent colors. You can easily choose of them for your #colorchallenge posts!
Mixing of light colors (additive) and pigment colors (substractive):
Just a little note: you can never make black by mixing any pigment colors. The result will always be a dark brown shade!
See more information here, here and here!
You can also learn about HTML-colors here!