He wrote the colours down the day he started: pale violet walls, a butter-yellow bed, lilac doors, a blue basin. The walls in the Chicago painting are blue now. That violet was cobalt blue mixed with a red lake he knew faded in daylight, and he went on ordering the red by the dozen anyway.
The list he sent his brother
On 16 October 1888 Van Gogh wrote to Theo from Arles with a sketch and a list. The walls pale violet. The floor red tiles. The bedstead and the chairs fresh butter yellow. The sheet and pillows bright lemon green. The blanket scarlet. The window green, the dressing table orange, the basin blue, the doors lilac. And that's all, he wrote, nothing in this bedroom, with its shutters closed. The colour was doing the work: looking at the painting, he said, should rest the mind. He took the shadows out and laid the paint in flat tints like a Japanese print, and decided the frame should be white because there was no white in the picture. He had just been made to rest for two days after a week of overwork, and he called the painting his revenge for it.
Three versions, because the first one got wet
He painted the room in October 1888, a month after moving into the yellow house, while he waited for Gauguin to arrive. The following spring the Rhône flooded Arles while he was in hospital there, water reached the house, and the canvas was damaged. From the asylum at Saint-Rémy he asked Theo to have it lined onto a fresh support. Theo suggested painting a copy first, in case the lining went wrong. In early September 1889 he reported that he had redone the canvas of the bedroom, and about three weeks after that he made a third, smaller version to send to his mother and his sister. The painting in Chicago is the second one. In 2016 the Art Institute put all three in one room for the first time.
The colour that left the room
Pigment analysis explains the blue. The walls and the doors were painted in cobalt blue with red lake mixed into it — carmine from cochineal, and the geranium lake he was fond of — and the two together make violet. The reds are fugitive. Light destroyed them, and what is left of the mixture reads as blue. A microscopic sample lifted from the painting still carries the original violet on its underside. He knew. In eight separate letters he asked Theo for geranium lake from the Paris colour merchants Tasset et l'Hôte, and ordered forty-four tubes of it in all. The room he described as restful was built out of a colour that was already leaving while he wrote the description down.
The bed is still butter yellow, exactly as he listed it. The walls were pale violet, and that is the part that did not keep.
Some stories are better over a coffee. Fifteen minutes with someone — audio only, not open yet.