Hair color - Demi Permanent vs Permanent?

Question

Why is it that when I use a Demi-Permanent hair color (Color Charm), the color always comes out darker than when I use a permanent hair color, comparing it to the color swatch?

Answer 1

demi is a wash out color so it starts out dark to last longer while permanent on the other hand is exactly what i says it is, it isn't going to go away. will it fade slightly? yes. but people think their colors fade more than they really do because they get used to it.

Answer 2

Demi permanent hair color just sits on-top of your normal color. Permanent color actually lightens it a bit (due to mixing it with the peroxide developer) before depositing color.