salted paper prints: a salt solution is applied as a base coat on the paper and a photosensitive silver nitrate solution is then coated on to the paper. The image is created by laying a negative (paper or film) or object (lace or flowers) on top of the paper and then exposing it to sunlight. Exposure time will depend on the strength of solutions, paper type, and strength of light.
Henry Fox Talbot: invented the salt process in 1833. He began first by coating the paper only with silver nitrate. Only a faint image was produced. Talbot found by coating the paper with a salt solution first, the resulting image would be much stronger.
Sir John Herschel: invented hypo in 1839. This solution was used to permanently "fix" Talbot's photogenic drawings and other photosensitive surfaces.
1. First we chose the paper that worked best in our last experiment which was watercolor paper.
2. We coated our papers one time with 2% salt solution and dried them completely.
3. The papers were then coated with a 12% silver nitrate solution twice (The paper was dried in between coats).
4. We also coated an extra paper to use to experiment with yellow, red, and blue filters.
5. The extra sheet was exposed to sunlight with yellow, red, and blue filters put on certain sections of the paper. My sheet was exposed to the sun with different keys placed on the paper.
6. The exposure time was about 3 minutes in direct sunlight.
7. The images were ten washed with water and then put through 2 hypo baths to fix (about 3 minutes per bath).
8. They then were washed in a running water bath for 30 minutes.
I used keys to create an image for my photogenic drawing. In the image you can see tonal variation between the parts of the paper that received direct sun, where the keys were, and the shadow around the keys. The paper was exposed for 3 minutes in the sunlight and although it seemed to be long enough, the image lightened up in the hypo baths. I think a few more minutes in the sun would produce a darker black and therefore more tonal separation in the image.
The paper that tested the filters was also exposed for 3 minutes. The blue filter produced the darkest value (almost as dark as without a filter). The blue filter allowed the shorter wavelengths through to the paper, therefore exposing the silver. The red and yellow filters did not let as much light through and therefore resulted in lighter tones.