Color theory is color theory regardless of what you are mixing. I have had very little trouble mixing to get a specific color of dye because I understand how colors react and mix together. Now because the dyes will actually separate and be absorbed at different rates, you can achieve variable results.
Many people think dyeing with Kool-Aid will only yeild bright colors suitable for children. People think that because the colors are bright that only bright colors can be obtained from Kool Aid dyeing. This is simply not true. People often assume that whatever they are doing, it's what they are using that is problematic, not that they don't know how to use the product to it's full potential. This is the case with Kool-Aid, and the above assumption on dyeing with Kool Aid and food colors.
The results are consistent and pretty limitless if you are willing to take the time to do the tests and keep records. Hopefully this information can be shared with others and the number of tests needed, would be lessened.
To begin getting a diverse palette of color using Kool Aid and food colors it is helpful to understand some basic color theory. Becoming aware with how colors interact and change each other will allow you to make your own new colors, and recipes for them. You will need to keep careful records so that you can repeat your results consistently. Measure your amounts and keep track of that as well.
The color wheel starts with primary colors, red , yellow and blue. You can combine these three colors to make all the other colors, to one degree or another. You can make any shade of yellow for example if you know which colors and how much to add, from sunshine to dark dull mustard.
So we all learned in grade school that when you mix two primary colors you get secondary colors. Yellow and red make orange, red and blue make violet and yellow and blue make green.
When you mix a secondary color with a primary color the result is a tertiary colors. These have two part names that indicate this mixing such as blue-green. Notice that one color in these names is primary and one is secondary. All this means is that Blue-green for example has more blue than yellow. Equal parts of yellow and blue make green, add more yellow and you get yellow-green. More blue yields blue-green.
A hue is the color (like yellow) but it refers to the color in it's pure form, with no white or black added. When you are adding white or black this is an indication of value not saturation. Adding black darkens and dulls a color, the hue and saturation stay the same, unless you add more of that original color. In dyeing this gets more complicated because black is made both a combination of other food colors in Wilton's Black for example. You can't really add white to lighten the color, but you can just add more fiber or less coloring to achieve a lighter color.
Now we know how to lighten or darken the color, how do we convert these to more natural, subdued colors? We add compliment colors to each other which will make a form of gray. Compliments are straight across the wheel from one another, such as 11 and 5. Gray in this case means any color that isn't a named color on the wheel, not just black and white mixed together. Browns are considered grays in this article and will be referred to as grays from now on.
So if we mix 11 and 5 we get a gray color (even though it's green looking) that is green in appearance and dark. This effect will vary from mix to mix. Keep track while you test for a certain color and keep careful records. Measure your amounts by drops for food colors and 1/8 of teaspoons for Kool-Aid dyeing. So if we did this mix, of 11 and 5 we get something like this. The colors on the ends are what mixes to make the middle color.
This would be about right for equal amounts of green and red.
Now I have to point out that this isn't what would happen with Kool-Aid, it would be more of what we call brown. This is because that the computer mixes light waves, and pigments are different, but the principal is similar.
If we add more green than red we get this:
Conversely adding more red than green gives you something like this:
One way to conduct tests is to add measured amounts of Kool Aid or food colors and water into a small glass jar, and microwave to set the dye. Remember that if you use food colors you must add some acid, such as vinegar, citric acid, crushed Vitamin C or fruit fresh.