Now that you mentioned Daguerre, I want to say something here:
Later, Nipps cooperated with Frenchman Daguerre, and they found that better image quality could be obtained by using polished silver plates. 1833 Niepce died suddenly, and Daguerre continued his experiment, and finally got a special step named "Daguerre Silver Plate Photography".
The process of Daguerre silver plate photography is as follows: put the silver plate into a sealed box filled with iodine, and volatile iodine combines with silver to form photosensitive silver iodide. Exposing silver iodide in a black box for more than 30 minutes will produce a hidden image, which exists but is invisible to the naked eye. Daguerre found that mercury gas can be used to "develop", and the most common salt can prevent the image from continuing to reflect and thus "fix". The image made by this method is still positive, and because there is no negative, each image is unique and cannot be copied.
Daguerre silver photography is very clear and full of details. The silver surface makes the image can only be viewed from a specific angle, otherwise it will be elusive. Sometimes, the observer only sees himself in the silver plate, which makes Daguerre's silver plate photography get a beautiful name "Mirror of Memory".
Although Daguerre has made brilliant achievements, please don't forget Nipps's initial contribution, the world's first photo: daylight painting.