Here's background artist Ralph Hulett painting fine art in the mid-sixties at his home studio (converted from a carport). The studio was too hot in summer and too cold in winter. There was always a small, electric floor heater glowing at his feet during the winter months as he worked on various paintings.
And here he is in the more comfortable 2-F wing of the Disney animation building a dozen years earlier, painting backgrounds for Lady and the Tramp.
(R.H. painted all the freaking time, which probably explains his facility with paint and brush. It's been my observation that when you play a lot of tennis, or lead guitar, or piano, you get better doing all those things...)
(An actual Lady and the Tramp background from an actual image grab on the internets.)