Final answer:
Use a light color to draw a line in a hairstyle to guide the eye in the desired direction, similar to how artists use lighter tones to attract attention and create form in drawings.
Step-by-step explanation:
To draw a line in a hairstyle in the direction you want the eye to travel, you would use a light color. This is because light colors tend to attract the eye more than dark colors and can help to guide the viewer's gaze in a particular direction. Just as in drawing, where techniques like hatching and crosshatching are used to create shadow and form, in hairstyling, lighter colors create a sense of light and draw attention. The principle behind this is similar to how artists like Michelangelo would vary tones using pencils of different hardness or apply washes of ink or color to create value in their drawings. The amount of water in the medium can also affect the value of color, leaving parts of the drawing more prominent and guiding the viewer's eye accordingly.