The Moon often appears in Krug’s works as part of fantasy landscapes, drawn from childhood memories of hot August nights by the calm lakes of Wisconsin.  According to the artist, the lower part, often underwater, represents a dream-like world, while the sky, with its Sun or Moon, represents the here and now.

Krug studied the techniques of etching and engraving as a student and was an early experimenter of silk screens. He strove to add surface textures like embossing, commonly seen in engraving, to screenprints. Some of his prints have up to fifty colors, and one print might take the artist three to five years to finish.