Restfarve

Restfarve is a term commonly used in Scandinavia, particularly in Denmark and Norway, to describe the concept of "rest-color" or "remaining color." It refers to the color that persists or is left behind after a dyeing process has been completed, or the natural color that shows through when a darker color is applied over a lighter one.

This phenomenon is particularly relevant in hair dyeing. When hair is lightened, its underlying natural pigments are revealed, which are typically warm tones of red, orange, or yellow. If a darker dye is then applied, the underlying restfarve can influence the final result. For instance, applying ash brown dye over hair with strong yellow undertones might result in a greenish hue, as yellow and blue (present in ash tones) combine.

Understanding restfarve is crucial for achieving desired color outcomes in hair coloring. Hairdressers use this knowledge to select appropriate toners and dyes to counteract or complement the existing undertones. For example, a violet toner is often used to neutralize yellow restfarve in blonde hair. Similarly, in textile dyeing, the restfarve of a fabric can affect the final shade, especially when dyeing light-colored fabrics with darker dyes or when attempting to achieve muted or desaturated colors. The concept highlights the subtractive nature of color mixing and how existing pigments interact with new ones.