Color is used to symbolize the changes in the boys, in their relationships, and in the society on the island through the course of the story.
The black color of the choir's robes is a foreshadowing of their following Jack into the roles of hunters and killers. Jack's red hair matches the color of the blood of those hunted and killed.
The creamy white color of the conch shell represents the peaceful calm that the boys struggled to maintain. As long as the conch was respected as bestowing authority to its holder, some semblence of civilization remained and restrained the boys' behavior.
Contrasting colors are clues to changes in the relationships and patterns of conduct on the island. When the white of peace, the green that represented life (all the plants that provided food and shelter), and the red of blood and death combined, it was a terrifying combination.
Demoniac figures with faces of white and red and green rushed out howling, so that the littluns fled screaming...three others stood still, watching Ralph; and he saw that the tallest of them, stark naked save for paint and a belt, was Jack.
In Lord of the Flies, the reader is gradually drawn into the dramatic story as the boys change from innocent schoolboys, shocked but exhilarated by their isolation on this most beautiful island with a "vision of red and yellow" (a bird) and a lagoon so inviting with "blue of all shades," contrasted against the "white" surf and "dark blue" sea. The reader is, therefore, made aware that appearances can be deceiving and color, used symbolically, helps him to recognize the potential for success or failure in what will follow. In chapter one there is still hope as 'pink" contrasts with "dense green," but there is also an apprehension as "Jack's face was white under the freckles," an intense white, a penetrating white almost, after having missed the piglet.
In chapter 2, Jack's "bright blue eyes...nearly mad," reveal that there is potential for him to be an asset or an obstacle to the boys' collective future. The innocence of the boys and their transformation as they become more savage, is, therefore confirmed through the use of color. At first, they are noticed for their "grey, blue, fawn" jerseys and their "brown, fair, black..." hair and the difference as Jack's choir approaches is noticeable as they are "hidden by black cloaks..." (ch 1) This vision forewarns the reader.
It is important to note that the conch is "deep cream..with fading pink," (ch 1), which creates a visual image of something reassuring and gentle and belies the ultimate image of the shell as it smashes against the rocks when Piggy is killed.
The "acres of black and yellow" used to describe the fire (chapter 2) reinforces the contradiction of this island; the beauty but the potential for destruction.
Jack's "dazzle paint," (ch 4) significantly alters Jack's appearance to the point that he feels as if he is "an awesome stranger." His "bloodthirsty snarling" belies the tranquility of the mere (lake) with its "white water-lilies."
In chapter 6 as the beast become more of a reality for the boys, color highlights the reality and the illusion. The "blue flowers of the mountain-side" are the constant but the gentle breeze appears to bring life to the dead parachutist and contradicts the reality. Simon will realize, too late, that there is no real beast and the description of Simon, in chapter 8, as a "small, brown image," against the pig's head with its "blackening" teeth and the "black blob of flies," basically seals his fate, as "the blackness spread."
The seeming lure of "chocolate-colored earth" (ch 12) is no longer mistaken for a sense of hope but only leads the reader towards the inevitable conclusion. However, when the naval officer arrives, color becomes a symbol of hope again as the "white-topped cap" is more than a match for Jack with his "extraordinary black cap on his red hair..." Evil has been defeated but it will forever be present.