The following text comes from Sir Ralph Payne-Gallwey’s Letters to Young Shooters (1892):
There are certain points by which you may know a useful retriever, I mean one likely to do his work well if properly trained; though to lay down any hard and fast rules as to the appearance of a retriever is out of the question.
Every dog is called a retriever that can gallop for a half-mile after a wounded hare, whether he is small as a spaniel or big as a calf, his coat black, red, or brown, or of all horrible mixtures black and white, and whether he is rough as a sheep or smooth as a rabbit; a pure-bred retriever does not exist, for he is a mixture of colley, sheepdog, setter, and Newfoundland, with a strain maybe of poodle and Irish water spaniel, the latter being the best cross of all
However, let his ancestors be what they may, the animal we term a retriever is the most valuable dog we have for service with the gun; and if he is capable of being trained to his work, it is a small matter what his pedigree may be (pg. 372-373).
Out of that vast canine melange came four breeds of endemic British retriever. For some reason, all of these British retrievers are derived from the St. John’s water dog.
But before retrievers became standardized, there were greyhounds and even small terrier crosses doing this work.
Virtually every reference to a retriever that one will find in the historical record is to a “half-bred” or “mongrel” retriever. Whether these dogs were truly crossbreeds or simply reflecting the diversity that was inherent in the retriever gene pool, one can only conjecture.
But the dogs did standardize. Part the reason for this standardization had its roots in the early years of the dog fancy, but even at the time, everyone wanted certain type of dog as a retriever. Even someone who recognized that retrievers were of mixed ancestry had some ideas about what a retriever should look like.
Immediately following the text about the “mongrel” nature of retrievers Sir Ralph Payne-Gallwey provides a list of what a retriever should look like. Even though he recognizes that other colors in retrievers existed, he makes it clear that only a black one will do. He prefers a smaller-sized retriever of the wavy-coated variety with a glossy coat. I don’t know how one gets a dog like that from his preferred poodle/Irish water spaniel cross!
So it was not only the dog fancy that wanted some standardization in retrievers; the shooting gentry had its own expectations of conformation. And one can see in the case of Sir Ralph Payne-Gallwey’s criteria it was not necessarily based upon the notion of “working conformation.” The black coloration, which was the preferred coloration, has very little to do with a dog’s working ability. (Immune function, however, is positively associated with melanism).
So even though the majority of retrievers were performance-bred mongrels, there were still selection pressures for a particular type.
And once one starts down that road, it isn’t a large move to standardize breeds from those outbred lines.
Golden Retrievers are one of my favorite breeds. My sister has a pure white golden. She is a very smart dog with a lovely temperament.
One reason for preferring solid black for retrievers, was to differentiate them from the largely white pointers and spaniels in the field. Another reason, is that a heavily coated white dog, or dog with white legs, shows the dirt and is more difficult to keep looking neat and clean.
And then, of course, there is simply “fashion”.