Dust process
In the dusting process in photography , chromic acid salt is mixed with rubber solution and grape sugar and this solution is allowed to dry on glass. The layer loses its tack in the light .
If you expose it under a positive image, it remains sticky under the black image contours, and if you then dust on dry color powder, it sticks to the areas that have remained sticky. In this way, the picture comes out in the respective dust color. This process has been used by Pizzighelli ( "Anthrakotypie und Cyanotypie " , Vienna 1881) with a few modifications under the name Anthracotype for the production of blueprints on paper.
If you used a negative image as the original, you get a negative image again. In this form, the dust method on glass is an important tool for reproducing fragile photographic negatives .
If you dust with porcelain paint, you get a burn-in picture, which after the coating of the layer with collodion can easily be detached from the glass under water and transferred to other surfaces (porcelain and glass dishes) and burned in. This is how you get the burned-in pictures on glass and porcelain. According to Grüne, a positive collodion image is made from a negative with the help of the camera obscura . This is immersed in a platinum solution, and here the silver of the image contours reduces the platinum. This is reflected in the areas of the image, creating a platinum image that can be peeled off the glass, transferred to porcelain and burned in.