Blue is a solid color which is actually light to dark grey and often has a bluish cast. The undercoat is also grey. Blue puppies are born silver, they look like the color of duct tape) or appear black before developing a silvery grey undercoat and a darker slate blue top coat.
Some Blues may be so dark that they appear Black until they are seen next to a black. The points (eye rims, nose, lips and pads) are blue.
To learn more about genetics visit blue & dilute or color genetics.
Blue
Blue Newborns 
Blue 8 wks 
Blue 6 mos 
Blue Adult 
Blue Adult
