Color and pattern male

Plumage: bright and as even as possible over the entire body; each feather grey-black, three or four times crosswise interrupted by a light-grey arched bar, which is not sharply defined. 

Ornamental feathers: the number of crosswise bars is larger in proportion to the length of the feather, the bars tends towards an inverted V mostly in the neck- and saddle-hackle; slightly white at the base of the tail is permitted, if it is not visibly disturbing from the outside. 

Pure/impure: cuckoo may be present in either purebred or impurebred males and is permitted; in a purebred the light-grey bar is clearly wider than the dark-grey bar, overall impression is lighter than the female; in a impurebred the light-grey bar is slightly narrower than the dark-grey bar, overall impression is similar to the female.

Down: light-grey, without barring.                                                                                                                                   

Serious faults

Completely mis-colored feathers. Strong yellow or rusty brown in the ornamental feathers. White in sickles and/or large steering-feathers and wing-flights. Too little barring in wings, tail and breast of impurebred.

Faults

A few mis-colored feathers. Barring in the down.

Color and pattern female

Plumage: similar to the male but appears darker because the light-grey cross-barring is slightly narrower than the dark grey barring. 

Serious faults

Too little shaft-stripe pattern. Too little barring in neck-hackle, wings and tail. White in wing-flights.Too little barring in wings and tail.

Faults

Slightly too light or slightly too dark color. A few off-colored feathers. Clear barring in the down. 

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.