Not to be confused with Black-and-White Drawing of Calvin.
Calvin in Black-and-White Form is a minor alter ego of Calvin. He appeared in a single Sunday strip (2/3 1991). He was identical to Calvin in appearance, but was black and white. He realized that the world had no any hue, value, or chroma. Calvin In Black-and-White Form was analogous to Calvin's imagination.
Behind the Scenes
Bill Watterson stated in The Calvin and Hobbes Tenth Anniversary Book that this strip was inspired by his fight with executives over whether or not he should license his work. Watterson was repeatably told that he was thinking of things in terms of black and white.