Jack uses white and red clay along with charcoal to camouflage his face when he embarks on a hunting expedition in chapter 4. Initially, Jack hopes that the face paint will disguise his appearance, making it easier to approach unsuspecting pigs in the forest. However, the face paint has another, more powerful function. Jack's mask allows him to feel "liberated from shame and self-consciousness" as he becomes increasingly savage.
By transforming his appearance, Jack feels free to behave like a barbarian without being embarrassed or feeling ashamed of himself. The mask allows Jack to take on a new identity that is violent, unforgiving, and bloodthirsty. Hidden behind the colorful clay, the id of Jack's psyche can flourish, and he embraces his inherent desires and primitive instincts. Wearing the painted mask, Jack is completely uninhibited and develops into a tyrannical, ruthless leader.
Jack's face paint also startles the other boys, who view him with fear and admiration. When Jack suggests that they join him on a hunt, Golding writes, "The mask compelled them" (89). The compelling function of the mask appeals to the boys' inherent savage nature and influences them to follow his lead.
Jack's painted mask also symbolically represents his transformation from a civilized English boy to a bloodthirsty savage. Once Jack paints his face, he is completely transformed and no longer thinks or behaves like a rational person. His exterior transformation has a dramatic psychological effect that contrasts Ralph and Piggy's normal appearance.