What does wet printing mean?

This is an ancient photography technique of19th century.

Wet-plate photography is a photography technique with glass or iron as the negative, which is an ancient photography technique from19th century.

At first, people wanted to have clear images and detailed shadows like the photos taken by Daguerre method, and print out many photos as cheaply and quickly as Carlo method. So someone put forward the idea of using transparent film base instead of paper base to make negative film.

"Egg White Glass" Photography In the19th century, only glass could be used to make transparent films. However, how can photosensitive drugs be attached to the glass? People began to look for a kind of transparent adhesive, which can not only stick photosensitive chemical materials on the glass plate, but also stand the development and fixing washing. The first thing people think of is to use egg white as adhesive. 1847, Nipps's nephew, Saint Victor, first obtained the patent right of "egg white glass" photography.

However, the photosensitive drugs mixed in egg white are very limited, and the exposure time is about 5 to 15 seconds, which is not suitable for taking pictures. However, it is very suitable for making "egg white photographic paper", and also suitable for developing photos and making slides.