Color and pattern male and female

Body feathering evenly medium-colored slate blue; each feather edged dark blue-black.

Neck- and saddle-hackle of the male and neck-hackle of the female shows darker.
Down: slate blue.

Serious faults

Completely or partially white, black or other colored feathers. Too dark or rust-colored blue. Missing or too unclearly defined lacing.

Faults

The above serious faults present to a lesser extent. 

Feather details from:  http://www.kippenencyclopedie.nl

Website from Johan Albada with more than:

         5000 photos of chicken-breeds, chicken color varieties and feathers.     

Genetic code: https://kippenjungle.nl/Overzicht.htm

Website from Henk Meijers with all available information regarding chicken genetics including the world famous: 

Chicken Color Calculator