Color and pattern male

Plumage: barring  must be clearly visible and as even as possible over the entire body; each feather lavender, three or four times crosswise interrupted by a white 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. 

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

Down: light-lavender, without barring.   

Serious faults 

Differently colored feathers. Too light lavender ground-color. Too wide barring. Yellow tint in the ornamental feathers. White in tail and wing-flights. 

Faults 

Slightly lighter or slightly darker lavender ground-color. Feather-vein darker than the feather. Too few barring on the tail.

Color and pattern female

Plumage: similar to the male but is less clear

Down : light-lavender, without barring.

Serious faults 

Differently colored feathers. Too light lavender ground-color. Barring too narrow. Insufficient barring on the hen.

Faults

Slightly lighter or slightly darker lavender ground-color. Feather-vein darker than the feather. 

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