Hair color formula / formulation

Think you can formulate your hair color ? I’ve browsed the home hair color section at wall mart out of curiosity. It left me clueless due to the lack of information on the box. I believe the pictures on the boxes are what happens to gray hair, but don’t hold me to that!      Basically hair color formulating is like mixing paint at Sherwin Williams. It starts with primary colors, red, blue, yellow and all colors in between, in all tones, lightest to darkest. Pick a color mix, tone and level, dark to light. Then figure it’s developer percentage (but the developer- that’s a whole different subject) sooo the thing is, that color in your bowl is mixing with the color in your hair. Yes your hair has color, unless you’re totally white. So for Example: if you have an red based haircolor in your bowl and apply it to your violet cool brunette hair, you’re  going to end up purple. It’s color theory. Pigmented hair contains color. 😉