Q: What is the ratio of color to cream developer? 1to1 means 1 oz. or what?
A: When mixing color formula with a developer (whether a cream developer or liquid) the ratio of 1:1 means that you combine equal parts.
Depending on how much you need, that could mean you combine 2 ounces of color with two ounces of developer (2 ounces is the standard
size bottle for most haircolor formulas) or one gallon of color and one gallon of developer. (You would never need so much color at one
time unless you are working in an industrial setting, such as wig making.)
The bottom line is you just want to use equal measure of hair color to developer to ensure best results.