imagine a line up of cars (they can be a random mix of paint jobs), but they are all covered in a white car cover, so they look white. these white car covers is the affect of c,c. The moment you have C+,c segregate, then this car cover will disappear, and you will see what other colour alleles may be present, so het or homo Blue (or any other allele for that matter) will become visible (but have been there all along)
His illustration points out that with two copies of recessive white (c/c) You will have a white bird, which is basically white covering a colored bird. But as soon as you remove one of these copies and you have C+/c The white is removed off the bird and the true colored bird appears. and as he points out these colors have been here all along but they have been covered with white.
by Jeffrey in BANTAM CHICKENS 1979 Published by ABA.Saiga Publishing Company, Limited Pub. Date: January 1977.
cc -- Recessive white --Changes both black and red to white. Working with recessive white can be tricky as it "white washes" a bird. It may have the phenotype of a totally different color or even a nonstandard color underneath the white. The only way to determine what the white is hiding is to mate it to a black bird. You can get barred, polecats, etc.
As you have probably seen on another thread a black bird is not required to knock the white off, about any color bird will do.