Q: If demi- and semi- haircolors are basically the same, why is it that a patch test is required for a demi-haircolor and is
NOT required for a semi-haircolor.
A: Iím not sure where you got your information, but both semi-permanent hair color and demi-permanent hair color should not be used
without performing a patch test first to determine possible sensitivity to the ingredient contained therein.
According to MiLadyís Standard Cosmetology textbook, both semi- and demi-permanent hair color
treatments require a patch test before using on any client. The fact is that demi-permanent hair color does use a very mild formula
developer (usually 3 to 7 volume peroxide) while semi-permanent color is merely formulate with smaller color molecules to allow the
color to penetrate the hair shaft and deposit color into the shaft of the hair.