White collies are called white colored if more than 75% of the body has white. They can be all white except the head markings or have one or several , large or small areas on the body of regular colors like sable, black & tan, blue merle, or sable merle. (depending on what the main regular color is in the genes of the collie)

White collies will most often always have a normal colored marked face of one of the regular colors of sable, black with brown/tan, sable merle, or blue merle.

If a collie has half or more of a white face then it is most often caused by other genetic reasons. Especially if the white covers across one or both eyes.

A white collie genetically needs both parents as white or "white factored". So if both parents are "non-white factored" then there can be no white collies in the litter.

A white collie is always "white factored".

A regular colored collie can be white factored or non white factored. A regular colored collie can look normal colored with no signs of white factoring.

There are often signs on a regular colored collie if it is genetically "white factored". Often the stifles will be white under the inside of the leg so much that the white looks like it is curving to the outside of the colored part of the leg. Also the whole under belly and groin of the white factored collie will have more white going across and down the legs.

A white collie will always have a whole litter of white factored puppies even if the other parent is not white factored.

A white collie bred to another white collie will have a whole litter of white collies, but some can still have areas colored blotches on the body somewhere. The heads will still have normal collie colored markings.

A white collie can be bred to a colored but only white factored collie and still have some white pups but not nessessarily all the pups will be white. It is possible to have no white puppies if one of the parents is not white but only white factored. But the whole litter still has to be white factored because of the "white parent".

Two white factored collies bred together can make white puppies. If both parents are not white but are "white factored" the litter might have some or all white puppies but might not have any white puppies. Each parent offers a white gene and offers a non-white factored gene to each puppy but the we dont know which gene that puppy inherited from each parent till we see it born. If that puppy gets a white gene from both parents then that pup will be white. If that pup gets a white gene from one parent and a colored gene from the other parent then that pup will be white factored but not white. If that pup gets a colored gene from both parents then that pup will not be white factored or white.

Some breeders dont like to own white or white factored collies because if two white factored collies are bred then they can make white puppies.  A breeder might not want to have white puppies because of the unknown markings that can show up in a litter of white puppies..

Often a white collie seems to grow the coat in an uneven balanced shape. The flank area seems to not grow hair long enough to match the rest of the coat. This of course matters only in the conformation show ring when lined up with the rest of the show collies.  This is not always true with all white collies