What technique is commonly used to achieve highlights?

Foiling is a widely used technique for achieving highlights in hair coloring. This method involves using thin sheets of aluminum foil to separate selected sections of hair that are to be highlighted. By applying a lightener or hair dye to these foiled sections, stylists can create a contrast against the base color, resulting in bright, defined highlights.

The use of foil allows for precise application and helps to isolate the highlighted strands, ensuring that the color develops correctly without affecting the surrounding hair. The foils also help to retain heat, which can enhance the lightening process. Overall, foiling is favored for its ability to deliver sharp, dimensional highlights that can look very natural.

The other options involve different techniques that do not specifically focus on achieving highlights. Brushing might refer to applying color in a sweeping motion but does not provide the same level of precision as foiling. Waving and curling pertain more to styling different textures in hair rather than coloring techniques aimed at highlighting.