Paper Daguerreotype?

While reading through HH Snelling's 1849 History and Practice of the Art of Photography, I came across an interesting section titled "Paper Daguerrotypes" in which the author describes a process developed by Robert Hunt. Paper is soaked in potassium bromide and then sensitized with silver nitrate. After exposure (a "four or five seconds" wet or "two or three minutes" dry) the paper is developed via mercury fumes and fixed with hypo, creating a negative for printing. I cannot find any other reference to this process online, and I am very curious to know more about it. It seems almost like a silver bromide emulsion, with the silver resting inside the paper rather than gelatin. I'm hoping to give it a go as soon as I can get some more KBr. I think it would be best to try and find a way around mercury development as well. I'm assuming either becquerel development or a more mainstream chemical developer would work? I am no chemist though. Does anybody have any other information on this process/who was using it?

The only real difference I see between this and a common salted paper print used for a negative is developing with mercury. This might have become practical had collodion not happened on the scene.

If mercury development works, though, it seems like Becquerel development would as well. Why don't you try it and let us know?

Retired chemistry professor responding...

I would never consider using mercury vapor unless I had a laboratory grade fume hood that is ducted to the outside available. Even then, I would still think twice about it.

The environmental costs of mercury (in all aspects of obtaining, using and responsibly disposing of it) are steep. Too steep, in my view, to be viable for art making. I put mercury in the same league with chromium salts in this regard.

I am not sure what your goal is other than experimenting with an old process, and I am usually all for experimentation, but please reconsider the use of mercury in this context.

fgorga said:

Retired chemistry professor responding...

I would never consider using mercury vapor unless I had a laboratory grade fume hood that is ducted to the outside available. Even then, I would still think twice about it.

The environmental costs of mercury (in all aspects of obtaining, using and responsibly disposing of it) are steep. Too steep, in my view, to be viable for art making. I put mercury in the same league with chromium salts in this regard.

I am not sure what your goal is other than experimenting with an old process, and I am usually all for experimentation, but please reconsider the use of mercury in this context.

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Don't worry, I'm well aware of the dangers mercury poses to both my health and the environment, I stated in the original post that I was hoping to find an alternative method of development :^)

Donald Qualls said:

The only real difference I see between this and a common salted paper print used for a negative is developing with mercury. This might have become practical had collodion not happened on the scene.

If mercury development works, though, it seems like Becquerel development would as well. Why don't you try it and let us know?

Click to expand...

Yes, it seems quite similar to a salt print. The only difference I see is in its reported speed- it's fast enough for practical in camera exposures according to the text. I'd guess that has to do with sensitivity differences between silver chloride and silver bromide? Sounds like a nice easy experiment !

I would have thought that a "paper dag" would be silver iodide, developed either with mercury or via the Becquerel method. From what I've read, silver iodide has a near-orthochromatic response, which would be useful. However, I suspect the result - if there is one - would need fixing.

Not paper daguerreotype, but that was my trial: https://illumina-chemie.de/viewtopic.php?p=61814#p61814

Made a few errors:

a) Not polishing the silver layer
b) The sensitization with iodine was not so good
c) Stupidly overexposed the plate...11 min with 365 nm UV is far to much.

My idea was to use a desiccator and evacuate it, to avoid the heating step and reduce the concentration of mercury vapors* which are generated. The outlet of the vacuum pump goes through "iodinated activated charcoal" (Jodkohle in German) which will adsorb the mercury fumes see the paper in: https://journals.sagepub.com/doi/pdf/10.1260/0263-6174.32.8.693
The other point is, that the volume of the desiccator is small and thus the amount of mercury. Plus, when evacuated and if it is airtight, the valve can be closed and the pump switched off, not sucking mercury vapors out of the desiccator.
Found in a book (Frühe Photographien - ihre Technik und Restaurierung from Martin Hansch) a description for minimizing the use and impact of mercury (from memory): The image plate was put in a holder, with the exposed surface down. As counterpart a plate with silver was used, which is amalgamated with mercury. The space between this two plates is very narrow and the amalgamated plate is slightly heated to develop the other plate. According to this book the amount of mercury was very tiny....so the development can be done outside or even at the balcony**

*= (in English) Source: https://illumina-chemie.de/viewtopic.php?f=17&t=4009&p=60684 (in German)


Edit: **= compared to the amounts from industry (okay they try to reduce it) and natural sources e.g. volcanoes https://www.sciencedaily.com/releases/2008/06/080629081932.htm


bj68

helenore said:

I'd guess that has to do with sensitivity differences between silver chloride and silver bromide?

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I've tried salted paper prints with bromide instead of chloride. As I recall, they didn't expose notably faster. So something else must be going on.

A common salted paper print requires a huge exposure (multiple minutes to tens of minutes in direct sun) because it's printing out. This takes a great deal of exposure (minutes to hours) with enlarging paper, too. Developing a latent image will inherently improve sensitivity; one might approach the sensitivity of enlarging papers, which are very much practical for in-camera exposures (even with pinhole).

You're right; I wasn't properly awake!

I am not sure what the point of making a paper daguerrotype is (apart from expreimentation - in which case why not.) The charm and unique attraction of daguerrotypes, as far as I understand, is the ability to define features at a very high sharpness with a mirror-like finish due to the nature of the near molecular level fineness of its sensitized surface. None of that will be true on a paper surface created by depositing a halide salt followed by silver nitrate treatment, so the final outcome will be perhaps no better/different than a typical paper process like salt prints, etc.

But then it might be unique in some other ways?

Just my 2c...

:Niranjan.

I'd guess that the image, which is formed from silver-mercury amalgam, would have a unique tone even on paper (Daguerreotypes are usually toned with gold chloride, which give them a golden hue, but gold toning on the paper substrate would likely give the purple/red tone seen in gold toning a gelatin print).

Potassium bromide is in the mail, excited to give this a try! I have a feeling becquerel development may not actually work, given that "traditional" dags used multiple halogens during sensitization, but becquerel dags require pure iodine. If mercury is to be avoided, it might be worth trying to use potassium iodide instead, as suggested by revdoc. Thankfully I've got some on hand!

helenore said:

Potassium bromide is in the mail, excited to give this a try! I have a feeling becquerel development may not actually work, given that "traditional" dags used multiple halogens during sensitization, but becquerel dags require pure iodine. If mercury is to be avoided, it might be worth trying to use potassium iodide instead, as suggested by revdoc. Thankfully I've got some on hand!

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Curious if you ever ended up giving this a try. If you did, can you share your results and if you found a way around the mercury?