I grant you that it’s not clear-cut, but nowhere in the book (that I can find) is Gollum described as being pale, or even lightly colored (except his eyes). Instead, Gollum is frequently, as I showed, described as being “black” in color. He is also being misidentified as an Orc, which are similarily described.
Do you mean the skin color? The reference to the color black here is clearly there because Gollum is in the shadows in a darkened cave.