Color block, when referring to hair coloring, is typically a cream or gel which can be applied to skin or hair to prevent hair dye from staining those areas. This is also commonly referred to as barrier cream and is generally applied around the hair line so if dye does happen to touch the skin, it will not stain it. The use of color block is very common in most hair salons.
Hair color can easily stain the skin and create a very messy and unprofessional look to any color job. Beyond this, most hair dyes contain harsh chemicals which should not come in direct contact with the sensitive skin of the face. Using a color block cream will protect the integrity of the color job as well as protect the skin from irritation. Another common use for barrier cream is in two-tone dye jobs. When a stylist is dying a customer’s hair with two different colors, as in highlight or “chunky” dye styles, he or she may use a color block cream to keep the two colors from bleeding in to each other.
There are several commercial brands of color block available. Some are designed specifically to protect skin, some to protect hair and some can be used on both. There are, however, homemade barrier creams which have been used for decades to achieve the same or similar results. Many who dye their hair at home use petroleum jelly around their hair line and neck to keep dye from contacting the skin. Other recipes use conditioner and cooking oils applied to the hair to keep color from bleeding.
Most commercial color block formulas are gentle on the skin. Some, however, may contain harsh chemicals or cause an allergic reaction. When buying a cream for personal use, it is advised the user reads the full ingredient list and does a patch allergy test 24 to 48 hours before dyeing the hair. Salons do not always have this luxury, so those with sensitive skin or known allergies may wish to ask for a full disclosure of ingredients.
Professional stylists will generally agree that barrier cream is not to be used in place of other safety materials when dyeing hair. The person handling the dye should always wear gloves and use protective cloths to keep clothing free of stains. Individuals may also need plastic wrapped around the shoulders or neck to keep dye from contacting the skin in these areas.