The use of photography invented by Daguerre

The photography invented by Daguerre used the silver salt method.

Daguerre photography, also known as "silver plate photography", is a method to develop the exposed silver salt coating by using mercury vapor, which is called silver salt method.

Daguerre photography was initiated by Frenchman Daguerre. It is a direct positive method that appears on silver-plated copper plates and cannot be printed and reproduced. It is the earliest photography method with practical value in the history of photography.

Daguerre photography is also called "silver photography". It was originally created by Daguerre, a Frenchman. /kloc-0 was published in the world on October 7th, and used around 1839 and 1860. This is the earliest photography method with practical value in the history of photography.

This is a direct positive method that appears on silver-plated copper plates and cannot be printed and reproduced. The "photo" produced by Daguerre silver plate method is a positive image recorded on a silver-plated copper plate. It has good clarity, delicate images and good preservation. Because it is essentially a relief image made of mercury, it will produce different effects from different angles.

The specific steps of the silver salt method are as follows:

1. Prepare a thin silver-plated copper plate, wash it, polish it, and silver-plate the polished copper plate.

2. Put it into a small box filled with iodine solution or iodine crystal, and smoke the silver surface with iodine vapor for 30 minutes, and the iodine vapor reacts with silver to generate photosensitive silver iodide.

Put this photosensitive silver piece in the cassette for later use.

4. Put the tapes together in the black box for shooting. The time is 15 ~ 30 minutes. Under the action of light, silver iodide is reduced to metallic silver with different densities according to the intensity of light, forming a "latent image". When shooting, this kind of silver disk is put into a square box camera with a lens aperture of F3.6, and the exposure time is about 1 minute. After shooting and exposure, the silver surface was developed by mercury vapor fumigation.

5. In the light-receiving part of the silver plate, mercury and silver combine to form amalgam with bright spots, forming a bright part in the image. The unexposed part of the silver plate has no amalgam and still exists in the form of silver iodide. The developed silver plate is fixed with baking soda solution.

6. Then rinse with water and dry to get the image of milky white amalgam. The shaded part is transparent, and the dark silver-plated copper plate surface can be seen. It becomes a positive photo.