In the context of this artwork, explain the François and Jeanne Trabuc of the Portraits.
François Trabuc, who was the chief orderly at Saint-Paul, and his wife, Jeanne both sat for van Gogh.  François Trabuc had a look of "contemplative calm" which van Gogh found interesting in spite of the misery he had witness at Saint-Paul and a Marseille hospital during outbreaks of cholera.  He wrote to Theo of Trabuc's character, a military presence and "small keen black eyes".  If it were not for his intelligence and kindness, his eyes could seem like that of a bird of prey.Van Gogh describes Jeanne Trabuc as a "washed-out kind of a woman, and unhappy, resigned creature of little consequence and so insignificant that I have a great desire to paint this dusty blade of grade.  I’ve chatted with her a few times when I was doing some olive trees behind their little house, and she told me that she didn’t think I was ill – indeed you would say the same right now if you could see me working."
Theo interest