Calotype process

Their connections and differences are as follows:

1. Sunlight etching: It is a technology that uses light to transfer images. It exposes the negative film and the shading film to the sun together, and etches the aluminum layer on the negative film according to the shading degree of the image, thus forming a groove and finally forming an image. This method is usually used to manufacture printed circuit boards, microchips, etc.

2. Silver disk photography: It is a technology to record images on a silver disk. It is through coating a layer of photosensitive adhesive on the silver plate, then coating the photosensitive adhesive on the black and white negative, then exposing, developing and fixing the silver plate and the negative together, and finally obtaining the image on the silver plate. This method is usually used to make printed matter, printing template, etc.

3. Carlo photography: it is a technology to record images on photographic paper. Put the photo paper in a black box, then put a glass plate coated with silver particles on the photo paper, and form an image on the photo paper through the penetration of light. This method is usually used to make artistic photos, scientific research and so on.