Cesky Terriers can be any shade of grey from charcoal through to platinum, but never black or white. Occasionally they also have tan or cream points.
Ridley Fialka

People looking at a litter of Cesky Terriers are often surprised, as the puppies are always born black. It is sometimes difficult for even the experienced breeder to predict exactly what shade an individual puppy will finish up, although very pale Cesky Terriers are usually showing some lighter hair growth by the age of eight weeks. These two photographs show Ridley Fialka with her 4-week-old puppies (left) and one of those puppies (Ridley Gadabout) as an adult.
Ridley Gadabout

Other colours:

L: Dark grey/Tan, R: Mid Grey
Ridley Zazrak, Nadherna Nina Ridley

Brindle is only acceptable in dogs up to 18 months old.
Lastarean Darebak

The brown colour is extremely rare.
Regent del Monte de Haya