The critical distinction is that, although highlights use thin slices of hair to color them, streaks use a larger volume of hair. Although highlights are elegant, streaks give the face a more prominent aspect. Because the highlights are much thinner, they have a softer appearance. Hair foils are a more comfortable alternative to streaks, when hair was dragged through perforations in a plastic cap to separate the hair being colored, for those of us old enough to remember them. Ouch! The amount of hair to be foiled is referred to as a full-head or half-head.
