Silver plating

Jalo Porkkala takes us through the silver plating process and the difference in toners and formulas.

Jalo Porkkala, Twin Columns, Silver plated image

For contemporary black and white photographic papers there is a special toning method that Judy Seigel calls Silver plating in her Journal of Post-Factory Photography, and Tim Rudman, in his Master Photographer’s Toning Book, calls Silver and bronze mirror toner. Rudman also throws out the question: The modern Daguerreotype?

Modern Daguerreotypes are certainly being made, but the silver plating process is not related to this process, although there is similarity in the appearance. I believe nicknames like a poor man’s Daguerreotype and false Daguerreotype are quite eligible for this technique. Sometimes a printmaker may feel like a magician or an alchemist when a black and white photograph magically turns to a mirror-like silvery image in a couple of minutes.

Successfully combining an adequate subject with the silver plating effect can produce an extraordinary photographic print, something completely different from what is customary today. When trying to achieve this shiny metallic look it is best to use glossy RC paper. Matte paper will look more like dull brushed silver. Fiber based paper will silver plate as well, but seems to require longer processing times, and the mirror effect of the finished print may not be as intense as with RC papers.

It is impossible to reproduce a silver plated print electronically or with printing inks. It is usually best to view a print in indirect lighting, spot lights will just reflect from the surface as disturbing hot spots or sparkles. Just like a real Daguerreotype, a silver plated print is often viewed obliquely, and depending on the viewing angle, parts of the image may appear in reversed tones. In addition, the paper selected determines whether the mirror effect is “pure” silver-coloured or mixed with shades of bronze or gold, or even more colours (usually red, orange or yellow).

Since the lighting and viewing angle are important for viewing a silver plated print, it seems that small hand-held images are more suitable for this technique than giant enlargements on the walls of an exhibition hall. A hand-held image also gives – just like a Daguerreotype – a strange three-dimensional impression, due to the high-gloss metallic reflections, seen by each eye in a slightly different angle.

There is a commercial product on the market, the Halo-Chrome toning kit, manufactured and sold by Rockland Colloid in the USA. The package sizes are 240 ml and 960 ml, including chemicals needed (bleach and toner) as stock solutions, and they come with short and clear instructions.

Halo-Chrome works well when used according to the instructions, but there are not many formulas available for a printer wanting to experiment with the chemicals and their proportions. Rockland Colloid does not inform of the Halo-Chrome formula, but from their material safety data sheets (MSDS) one can see that the bleach contains copper chloride and the toner is made of sodium hydroxide, and there is some ammonia too in the mix. But, solely on the basis of this information it is not possible to clone the Halo-Chrome.

But it is possible to find other sources. In her Post-Factory Photography Judy Seigel has published silver plating formulas found in the Svensk Fotografisk Tidskrift magazine from 1947. In her article she reports on her experiments and experiences with some modern photo papers. In my tests I found Judy’s toners a bit weak compared to the Halo-Chrome; the processing times are longer, and sometimes it seems like the toner activity suddenly drops in the middle of the toning process. My recipes are a little stronger, and I prefer to use a little more liquids instead of the usually recommended 100–120 ml one-shot chemistry (for an 8×10”/18x24cm paper).

There are a couple of strange chemicals in the formulas – not many of us have hydroxylamine sulfate or hydroxylamine hydrochloride in our chemical cabinets. They may be somewhat difficult to find, check with your chemical supplier, or see the Chemicals page.

Chemical criteria

In the silver plating toner the silver halides are reduced to metallic silver. If a pre-processed black and white photograph is to be toned, it has to be bleached to form silver halides – you can use the bleach from the Halo-Chrome kit or you can mix your own (see the formulas below). If the print has been fixed with any of modern ammonium based (rapid) fixers, or the type of the fixer is not known, Tim Rudman recommends fixing again with plain hypo (sodium thiosulfate, see the formulas). With ammonium fixed prints toning may be uneven, and the mirror effect may fail partly or completely.

After one minute rinsing the bleached print can be moved to the toner. It should be toned, with constant agitation, for 1 to 2 minutes (RC paper), 2 to 4 minutes (fiber base), or until the silver plating is completed and the image will no longer change. The whole process can be done in normal room light.

If the image is now completely silver plated (the process was not aborted) another fixer is not needed, just wash the print in running water. However, silver plating can also be done partially, by shortening the processing time (e.g. when looking for a specific appearance). In this case, there will be un-toned silver halides left, and fixing is needed for image permanence. Finally, wash as you normally would.

Since the toner only works on the halides, which no longer exist in the highlight areas of a normal photograph, only the parts containing some density can be silver plated with this indirect toning method; the shadows will become silvery and the highlights will remain as they were. But also direct toning can be done, in that case no bleach is used. Toning is done during the normal processing then, after the developer and before the fixer. The process is carried out under the darkroom safelight.

After the developer the silver in a black and white paper is in the form of halides, most of them are in the image highlights where least silver has been reduced to dark metal. After developing and rinsing the print is treated with the silver plating toner, and the light areas will be silver mirrored while the deep shadows will remain as they were. After toning the print will need to be fixed and washed normally.

Technical treatment

It is advised by Halo-Chrome user guide to make prints relatively contrasty. It seems to be true that low contrast and dark prints easily lose their tone separation, and if, in addition, a print is toned until the very maximum, the result may be like a shiny mirror surface with little of the original details visible.

The technical execution of the toning can cause problems too; for even toning the print has to be agitated quite vigorously all the time. The toner will not last very long as a working solution (maybe a couple of hours max), so it is best to use it one-shot as small quantities. A flat bottom tray is recommended, so less solution is needed to cover the print. I typically use 140–160 ml for a 8×10” print. The toning should be started as evenly and quickly as possible; a good technique seems to be to pour the toning solution into the tray, then tilt the tray about 45 degrees so that the liquid is on one of the longer sides of the tray. Then put the print into the tray, and level the tray quite quickly so the toner will flow over the print evenly. Now start agitating and do it constantly, keeping the toner moving over the print. Due to chemical reactions the toner will darken during the process. Halo-Chrome instructions say that after the first print another one can be toned with the same small amount of solution. Whether you really can do this depends on the tone range of your image and your toning time; images with large areas to be toned consume more toner efficiency. If the toner is only slightly discoloured after toning the first print, it is probably possible to tone another one. But if it is black, or very dark, it has to be replaced with fresh solution.

There are a couple of factors of inconvenience in the darkroom, namely, the smell of ammonia (not dangerous but uncomfortable) and the caustic soda, sodium hydroxide, in the toner. Good ventilation and protective gloves are very useful. The chemicals are not very toxic per se, and they can be poured down the drain with plenty of water.

Finishing and storage

The silver plated surface of a toned print is very delicate and prone to scratches and stains, both during toning and the wet process after that. It is a good idea to print with wide margins that will make handling wet prints easier. Treat only one print at a time in a tray, or if there are several prints in wash at the same time, don’t let them touch each other. Even when dry, the prints are more delicate than normal photographs. Handle them with care and keep them in protective sleeves if possible.

A silver plated photographic print may not be considered fully archival. With time a print may lose some of its silvery shine, and the silver may darken throughout, evenly or unevenly. The phenomenon is similar to Daguerreotypes; air pollution and UV-light have their effects on image longevity. Daguerreotypes are normally kept in airtight cases. Something like glossy spray photo varnish could be tried on silver plated prints.

Chemicals

Developer: Any standard black and white paper developer (only for direct toning)

Stop bath: Normal stop bath for black and white papers.

Fixer: 10% hypo (100g sodium thiosulfate to 1000 ml water).

Copper bleach: From the Halo-Chrome kit, or by mixing

  • 17g sodium chloride (table salt)
  • 17g copper sulfate
  • 8ml hydrochloric acid
  • 500ml distilled water

This is the stock solution. For working solution dilute with tap water 1:1

Silver plating toner: From the Halo-Chrome kit, or by mixing

Formula 1

  • 4g hydroxylamine sulfate
  • 12g sodium hydroxide
  • 100ml ammonia (25%)
  • 200ml distilled water

This is the stock solution. For working solution dilute with tap water 1:8

Formula 2 (with hydroxylamine hydrochloride added)

  • 4g hydroxylamine sulfate
  • 2 g hydroxylamine hydrochloride
  • 12g sodium hydroxide
  • 100ml ammonia (25%)
  • 200ml distilled water

This is the stock solution. For working solution dilute with tap water 1:8

There are no big differences in results between these formulas. I recommend starting with the formula 1, so you don’t need to buy the hydroxylamine hydrochloride. If you like the silver plating look and wish to continue with the process, the formula 2 may produce slightly better mirror effect with some papers. You can also try to get better silvering by adding a little old developer to the toner, start with adding 20–30% of the working strength paper developer.

The process, step by step

Indirect toning (for fully processed b&w prints, in normal room light)

1Fixer
See Chemicals (if previously fixed with ammonium rapid fixer, or the type of the fixer is not known), 3–5 minutes.

2 Wash
2–3 minutes (RC paper) or 10–15 minutes (fiber base) (if you don’t fix, soak in water and continue from here on).

3 Copper bleach
Until completely bleached or as desired.

4 Rinse
One minute in running water.

5 Silver plating toner
With vigorous agitation, 1–2 minutes for RC papers, 2–4 minutes for fiber base papers. Fixer again, if not toned to completion.

6 Final wash
As in normal paper process.

7 Drying
Treat for one minute in wetting agent (Kodak Photo-Flo, Ilford Ilfotol, or similar). Don’t wipe the surface with anything, just hang to dry and let the water flow off the surface.

Jalo Porkkala, Chalon, Silver plated image


Direct toning, no bleach used (done in safelight)

1In addition to the basic b&w chemicals, mix a one-shot toner in a flat bottom tray (formula 1 or 2, ca 40–160 ml for an 8×10” paper).

2 Developer
Expose and develop as you normally would.

3 Rinse
One minute in running water.

4 Silver plating toner
With vigorous agitation, 1–2 minutes for RC papers, 2–4 minutes for fiber base papers, or until the silvering process seems to be completed.

5 Rinse
One minute in running water again.

6 Fixer
See Chemicals, 3–5 minutes).

7 Final wash
As in normal paper process.

8 Drying
Treat for one minute in wetting agent (Kodak Photo-Flo, Ilford Ilfotol, or similar). Don’t wipe the surface with anything, just hang to dry and let the water flow off the surface.

Further reading

Rudman, Tim. The Master Photographer’s Toning Book. The Definitive Guide. London: Argentum, 2002. Reprinted 2010.

Seigel, Judy. The World Journal of Post-Factory Photography. Issue #3. New York: Post Factory Press, 1999.



One Comment

  1. yashasvi
    Posted October 22, 2013 at 8:10 pm | Permalink

    can it also be done on vandynk prints??

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