Around 1980 I worked in a professional two-rooms darkroom in Paris. In one room were three enlargers (Focomats Ic and IIc, and a 4x5 enlarger, probably a Beseler). Each enlarger had its own timer. This room had no windows. The second room had two large sinks, the first for the trays with chemicals, the second for washing. The door between the two rooms was open most of the time and it had a clock on it that we used as soon the exposed print went into the developer. My job was the wet part: I was either given the exposed print, or I went into the first room and collected it from a drawer the printer had put it in.
The clock was vital because we could both see it. The second room had windows to a courtyard and we had blinded the windows with red foil. This meant we could see the courtyard which was great because there were days we worked here from 8am to 8pm. In addition to the red foil we had installed these black roller blinds for when the sun was too strong.
When the door was closed it was 100 percent dark in the first room, this was where we loaded film into developing tanks . . .
One of the bigger jobs we'd do was print editions. Editions of up to 100 prints of one negative. Closing the door was vital for that because, after tests, the printer would only expose all the sheets and put them in a box in a drawer. Doing that number of prints could take hours and I would be in a third room doing other work, retouch, pressing prints flat, cutting up film, etc. But once he had finished printing the edition of one negative I went back into the second room and processed them. All at once, that is another story.
These days my darkroom is in my workspace, which is one large room. I am able to make it all dark. I like it a lot to move around in a very large darkroom, it is a different story. More space means more dust. One needs to keep it clean . . .
Each room must have been about 3x3meters ...