What does the 'foil technique' in hair coloring involve?

The foil technique in hair coloring is characterized by its use of foil to isolate specific sections of hair while color is applied. This method allows for targeted highlighting, enabling the stylist to create distinct strands of light and dark. By wrapping each section of hair in foil, the heat generated from the scalp helps to intensify the color processing, allowing for vibrant, well-defined highlights or lowlights. This technique is favored for its precision and the ability to achieve a multi-dimensional look without the colors bleeding into one another.

Other methods that involve applying color with a spray bottle or using a comb do not provide the control and isolation that the foil technique offers. Blending hair color evenly, while important in the overall coloring process, does not specifically relate to the foil technique's distinct method of application and results. The use of foil thus plays a crucial role in creating specific highlights and enhancing the overall color effect in a way that other options cannot replicate.