One of my favorite artists is John Singer Sargent, who is best known, perhaps, for his society paintings. "Portrait of Madame X," etectera.
Like most artists revered for their portrait work, Sargent... got tired of doing it by the time he was forty. And, lucky for him, by that time he had enough money to travel and indulge himself in making some very beautiful watercolors--many of which are my personal favorites of his work.
Tonks was not an easy man to know. A physician before he became a painter--and during World War I, he became, for a time, physician again. Appointed an official war artist in 1918, he painted a series of uncompromising portraits of wounded soldiers which I do not recommend looking up on the internet unless you want to be upset. One of Tonks's early students, from the time Tonks was teaching in London, wrote:
"Tonks cared nothing for other authorities and he disliked self-satisfied young men….His surgical eye raked my immature designs. With hooded stare and sardonic mouth, he hung in the air above me, like a tall question mark, moreover… of a derisive, rather than an inquisitive order. In cold discouraging tones he welcomed me to the Slade. It was evident he considered that neither the Slade, nor I, was likely to derive much benefit.
And, even better, some great satirical images remain for us, out of that decades-long friendship. They were "official painters" of the war together (~1918), but also traveled and enjoyed each other's company both before and after that. The details of these images are particularly fine. Note that Sargent, in the third picture, is being "belayed" on his mountain perch by two rope-wielding assistants, and he has set up his easel on the top of a mountain route--as evidenced by the heavily packpacked climber, trying to crawl up into the picture...!
The images are all linked through to the Boston Museum of Fine Arts--click through, if you like, for more details.