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Photogenic drawing is a type of contact printing in the history of photography. It was invented by William Henry Fox Talbot, a gentleman scientist, which he announced in 1839. Paper is immersed with salt solution, NaCl and distilled water, and then allowed to dry. Silver nitrate is then brushed on the sheet of paper. A chemical reaction occurs in the paper to produce silver chloride, making the paper light sensitive. When an object is placed on top of the paper (contact) and then exposed to light, the uncovered sections will darken and a light image is left. Until the image is fixed on to the page, the image can darken to the surroundings and disappear. The negative image can be fixed by immersing the paper a salt saturated solution – the salt prevents the silver from reacting further. John Herschel picked up Talbot’s research and came up with a new method for fixing the image to the page. His hypo fixer (sodium thiosulpahate) dissolves away silver nitrate and became the standard for all silver processes.
The exposure time can vary, depending on the quality of light and the solution concentrations. In bright sunlight, the image will appear faster. However, in other light, it may take several minutes to appear. In our experiments where photosensitive paper was exposed in light boxes we left the images exposed for about five minutes. Though unknown, further exposure may have proven to darken the images.
The solution concentrations effect the outcome of the images. For our experiment, we used two concentrations of salt solution, 2% and 10%, and two concentrations of silver solution, 5% and 12%, and four types of paper. Using every combination on each paper:
2% Salt, 5% Silver
2% Salt, 12% Silver
10% Salt, 5% Silver
10% Salt, 12 % Silver
The four types of paper on which those tests were performed were:
A) 100% Rag
B) 400 Series Strathmore water color cold press
C) Carton Bristol board – regular surface texture
D) Strathmore Gemini 140lb- rough
There was a total of 16 tests. However, when preforming the last tests, (2% salt, 5% Silver) (2% salt, 12%), it was suggested to try a double coat of silver nitrate and so half the strips were coated in a second coat of silver, adding 8 more results to the final total.
The concentrations were decided in a previous class session and made with distilled water, as tap water can contain chloride which would react with the silver before it is supposed to react on the paper. With the lights off and the shades drawn in an attempt to prevent premature light reactions on the paper before exposure. Strips of paper were cut from each type of paper. One of each type was taped to a board – tape on all sides to help with the natural bubbling of paper when saturated with fluid. In the end there were four boards with four different strips of paper across them for each test of solution combinations. On the lower salt concentrations test another piece of paper was placed down the middle to divide each strip into two sections, one for one coat of silver, and one for two coats of silver.
Salt was applied first. Two lines of salt water from a pipette were drawn across the top of each strip and then with a sponge brush spread across the paper. The pipette was necessary to prevent contamination as residues from the paper could get into the overall solution if the brush was dipped into it and a reaction could taint the solutions. The application process of two lines across the top of the strip, going lengthwise, and then spreading it with a sponge brush was used for each application of every solution. A blow dryer was used to dry each coat between applications.
The following are the observations for each test, with a key for which papers are which.
Key:
A) 100% Rag
B) 400 Series Strathmore water color cold press
C) Carton Bristol board – regular surface texture
D) Strathmore Gemini 140lb- rough
Salt = NaCl
Silver Nitrate = AgNO3
**** Keynote: the less salt and higher silver, the better reaction****
Experiment 1) 2% Salt NaCl & 5% Silver Nitrate / half of this sample had 2 coats
Observations: Before exposure, Paper A changed. The second coat of silver turned the darkest brown with uneven distribution on the singular coat. Paper B had no change before exposure, but after turned a deep purplish color. Paper C turned a greenish brown before exposure, very pale. After exposure two coats were dark whereas the singular coat of silver had hardly any change. Paper D had very little change before exposure. After exposure, two coats turned dark whereas the singular coat hardly changed at all, though it seems primarily due to uneven distribution of solutions.
Below, A-D, Bottom to top
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| Experiment 1 before exposure, two coats applied on left half |
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| Experiment 1 after exposure of five minutes, before fixing the image. See the uneven exposure when there is only one coat of silver. |
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| Experiment 1 after photo fixing in salt solution, rinsed and air dried with blow dryer. See faded contrast with fixing immersion. |
Experiment 2) 10% Salt NaCl & 5% Silver Nitrate
Observations: There were no visible changes before exposure for any paper. However, after exposure there was limited changes. Papers A and B had slight yellowing. Paper C became a light purple tint. Paper D had the highest level of contrast, an almost purple tint. Below: Paper strips in the order from top to bottom D-A.
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| Experiment 2 after five minutes exposure. See very light change in contrast. |
Experiment 3) 2% Salt NaCl & 12% Silver Nitrate / half of this sample had 2 coats
Observations: Paper A turned brown with second coat of silver before light box exposure. After exposure, second coat darkened whereas singular coat hardly changed. Paper B turned a very light brown before exposure but remained a light (though darker brown) after exposure. The singular coat proved to have poor evenness in change. Paper C turned dark brown, a little orangish, on the second coat of silver before exposure. After exposure, the colors darkened, however, the singular coat was uneven in distribution and seemed darker than two coats of silver that remained orangier than the single coat. Paper D turned light brown before exposure on second coat, however, both darkened with exposure to light.
Below, from left left to right A-D
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| Experiment 3 before exposure, two coats Silver applied on lower half |
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| Experiment 3 after exposure of five minutes. Observe darkened sections and lighter sections where objects had blocked the light. Uneven sensitivity in 1 coat upper section. |
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| Experiment 3 removed from tape and images fixed. The contrast is diminished in the fixing process. |
Experiment 4) 10% Salt NaCl & 12% Silver Nitrate
(all of these had some contrast)
Observation: No change before exposure. After the exposure: A. Little Change, B. Little to NO change, C. Little Change, D. Little Change
Below, A-D, top to bottom
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| Experiment 4 after five minutes exposure. See the very light change after exposure. The increased salt concentration keeps the silver from forming a good photosensitive surface. |
รจ C & D on all tests were, in most cases, wrinkled due to the amount of liquid absorption. Also there seemed to be yellowing of these two papers.
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| love-in-a-mist photo by Ian Talbot |
