What were the requirements for taking a portrait of Daguerre at that time?

At that time, photographing Daguerre's portrait was a severe test. First of all, you have to wear the right color clothes, because Daguerre photography is only sensitive to blue and white, and all other colors are black. Therefore, wear blue or white clothes when taking pictures. At the appointed shooting time (it must be sunny and cloudy with insufficient light), you have to climb several stairs to reach the studio. This is a glass house, usually built on a flat roof. When you come in, you should sit in a chair on the high platform with your head fixed with an iron clip and your eyes fixed on the camera. You can't blink.

Then, the assistant put the photosensitive metal plate into the camera and exposed it for 30 seconds to 1 minute. If you want two photos, you can take them twice in the same way, or you can take them side by side with two cameras.