This painting is by Sir Edwin Landseer. The black and tan dog holding a brush in his mouth is obviously a retriever– one that may have been upon crossing black-and-tan (“Gordon”) setters with some form of Newfoundland. The other two look to be other prototypes for a retriever– a pointer cross and a poodleish terrier-type.
Black and tan individuals occasionally pop up in Labradors, which means that the black and tan coloration was evident in Newfoundlands and St. John’s water dogs.
It is amazing that this retriever has an expression that so resembles that of a modern golden retriever. Indeed, if this dog had been a golden one, we might mistake it for a descendant of the Tweedmouth strain.
I’ve seen a lab where the tan points were brindled, at Guide Dogs. I asked a friend who works there if the dog was a crossbreed, but she said he’s pure lab. The base and the brindling were both quite dark.
Think the other brownish dog is a collie.
These two larger dogs (or extremely similar ones) also appear in a self-portrait that Landseer painted: the dogs are peering over his shoulders as if considering what is depicted in whatever Landseer is painting. L. is holding brush in his right hand. It is possible that they were Landseer’s own dogs.