Herp Hues

Snakes body is covered with scales. Scales composed of transparent beta keratins get their colours from pigments in the inner layers of the skin. Scales are hued for all colours except for blue and green. Blue is caused by the ultrastructure of the scales. By itself, such a scale surface diffracts light and gives a blue hue, while, in combination with yellow from the inner skin it gives a beautiful iridescent green.
Seen in the pic is an example of how the hues in scales colour vary.

Small: A4: 11.69 X 8.27 inches
Medium: A3: 16.53 X 11.69 inches
Large: 2 X 3 feet : 24 X 36 inches