"He was a Gollum - as dark as darkness, except for two big round pale eyes in his thin face."
Gollum is another Tolkien character who is is usually represented visually in a certain way regardless of what the text says. The following is an excerpt from a
Wikipedia article about Gollum's appearance:
Tolkien describes Gollum as either dark, bone-white or sallow (pale yellow): at one point the Men of Ithilien mistake his silhouette (seen from a distance) for a tailless black squirrel. In a manuscript written to guide illustrators to the appearance of his characters,* Tolkien explained this by saying that Gollum had pale skin, but wore dark clothes and was often seen in poor light. The Hobbit states he has pockets, in which he keeps a tooth-sharpening-rock, goblin teeth, wet shells, and a scrap of bat wing. Despite these details, he is generally depicted wearing a loincloth or naked in illustrations and adaptations.
*citation: Hammond, Wayne; Scull, Christina (2005), The Lord of the Rings:
A Reader's Companion, London: HarperCollins, pg 447, ISBN 0-00-720907-X