The canvas is in two pieces. An L-shaped strip along the bottom edge and up the right-hand side was cut off after Toulouse-Lautrec died, and what it took away was the dancer May Milton and her green face. By 1914 the strip had been joined back on.
Why she was in the way
The Moulin Rouge opened in 1889 and was built for electric light, which was new, hard and came from the wrong direction. Toulouse-Lautrec liked what it did.
May Milton leans in at the right edge with her face lit from below, chalk white going to acid green, her mouth red — the one thing in the picture that does not look like an evening out. The likeliest reason for the cut is a dealer's: a group portrait of a nightclub will sell, and a green head staring out of the corner of it is harder work.
Nobody put their name to the decision. What is on record is that the canvas was severed after the artist's death and rejoined before 1914, and that it is one picture again.
Everyone at the table has a name
This is not a crowd scene. It is a group portrait of people who can all be named. Round the table: the writer Edouard Dujardin, the dancer La Macarona, the photographer Paul Sescau, the wine merchant Maurice Guibert, and Jane Avril with her back turned, known by the red hair.
Standing behind them, doing her own hair, is La Goulue, the most famous dancer the place had. In the middle distance there is a very short man walking beside a very tall one: Toulouse-Lautrec and his cousin Gabriel Tapie de Celeyran, who was a doctor.
Lautrec had a table permanently reserved here, and an earlier painting of his already hung in the lobby, bought by the owner as decoration. He was painting his local.
What the light was for
Cafe-concerts were all over Paris in the 1890s and the Moulin Rouge was the one everybody had heard of. What separated it from a bar with a stage was the electricity: a room lit from fittings instead of flames, bright enough to turn a face into a colour rather than a shape.
Most painters treated that as a problem to be softened. Lautrec treated it as the subject. The greens and the whites in this picture are what no flame produces, which is how you can tell what kind of light he was standing in.
He died in 1901, at thirty-six. The strip with May Milton on it went back where it belonged within thirteen years of that, and the painting has been in Chicago since the 1920s.
He had a table permanently reserved at the place. Everyone who sat at it got painted, including the one they cut off.
Some stories are better over a coffee. Fifteen minutes with someone — audio only, not open yet.