Foil highlights are a hair coloring technique that involves using thin sheets of aluminum foil to separate sections of hair. This method allows for precise application of hair dye or lightener, creating a more defined and natural look. The foils help to isolate the highlighted strands, ensuring that the color develops evenly and reduces the risk of overlapping with other hair. The process typically starts with the stylist sectioning the hair and applying the color to selected strands. Once the dye is applied, the foils are folded around the hair to keep it contained. This technique is popular for achieving sun-kissed effects or adding dimension to the hair, making it a favorite among many clients seeking a fresh look.