What characteristic of the dorsal markings usually results in the overall 'faded' appearance?

Answer

The edges of these blotches are usually diffuse or smudged rather than sharply defined.

The blurring effect created by the blotches having diffuse or smudged edges is what contributes most significantly to the overall 'faded' appearance of the pit viper.

What characteristic of the dorsal markings usually results in the overall 'faded' appearance?
animalreptileserpentviperRattlesnake