Final answer:
In a tint back service using Shades EQ, the filler formula depends on the desired end result and the client's natural hair color. It is important to consult the Shades EQ color chart for the correct shade.
Step-by-step explanation:
In a tint back service, a filler is used to replenish any missing pigments before applying the final hair color. In the case of a Shades EQ tint back service, the formula for the filler will depend on the desired end result and the natural hair color of the client.
It is important to consult the Shades EQ color chart provided by the manufacturer to determine the correct shade for the filler. The formula typically consists of a mix of the Shades EQ hair color and the Shades EQ Processing Solution, in the ratio specified by the manufacturer.
For example, if the client's natural hair color is a Level 6 and the desired end result is a Level 7 copper, the filler formula might be a mix of equal parts of the Shades EQ 07R Copper and Processing Solution.