What does "double process" mean in hair color?

"Double process" in hair coloring refers to the technique of first applying a bleach to lift the natural hair color, which lightens the hair, followed by applying a toner to achieve the desired final shade, often a more specific or nuanced color. This method is particularly effective for achieving lighter shades, as it allows for the removal of underlying pigments before applying the desired tone.

The initial step of bleaching is crucial, as it creates a blank canvas by lightening the hair, while the subsequent application of toner adds the chosen color. This two-step process permits greater control over the final result, helping to ensure that the hair looks vibrant and true to the desired shade.

In contrast to the other options, applying a toner first would not effectively lighten the hair nor prepare it for coloring, mixing different colors lacks the systematic lifting and toning process, and using two different brands of dye does not inherently involve the double process methodology. The emphasis on bleach followed by toner clearly designates the steps involved in a true double process.