Schwarzkopf 5-3 light-matte-brown, permanent hair color requires a color/developer ration of 1:1 by volume. There are four levels of Igora Royal developer for use depending on the level of color desired, with percentages of 3, 6, 9 and 12.
The developer needed for coloring depends on the desired tone shift. The 3 percent developer lightens hair by one tone and the 6 percent is for matching tone-on-tone or minor lightening. The 9 percent developer is for lightening by 1-2 tones, and the 12 percent lightens by 2-3 tones. The Schwarzkopf line of hair color is sold for professional use, and care should be taken when using outside a salon.