Famous Should Hair Be Shampooed Before Coloring Ideas. Web there are two good reasons to skip the hair washing session before applying hair dye. Web you should always do an allergy test 48 hours before you dye your hair.

Will oils and gunk affect the color’s ability to take? Web you should not wash your hair right before coloring it. Web “buildup such as mineral deposits from water and products can fade color a bit,” she says.