Gilding

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Gilding is the process of chemically adding a fine layer of gold to a daguerreotype. This enhances the appearance of the image and improves it's durability.

Gilding Solution

Part A: 1 gram Gold Chloride in 500 mL distilled water (0.2% solution).
Part B: 4 grams Sodium Thiosulfate in 500 mL distilled water (0.8% solution).

Parts A and B are mixed 1:1 right before use.[1]

In preparing the gold chloride solution add the gold chloride to 400ml of distilled water. Rinse the glass vial or ampoule with distilled water into the solution and top up the solution with more distilled water until it is 500ml. Filter the solution and store in a 500ml amber bottle.

When mixing the A and B solutions, always pour the gold into the sodium thiosulfate solution. The yellowish gold solution will turn clear as this occurs. If you pour the thiosulfate into the gold, a brown precipitate can form in the solution. If the precipitate does form, the solution can be reclaimed by adding a couple teaspoons of table salt to the solution and letting it sit overnight. It is also best if your working strength gilding solution is filtered just before use.

Gilding

stand for leveling the plate.
When gilding the plate work in a strong light so you can see the changes taking place. Using a gilding stand that lets you make slight adjustments in inclination is key to getting a level plate. Ensure dust particles are blown off the plate before pouring on the solution making sure you have mixed enough to cover the plate but not needlessly waste solution (practice amounts of water on your plate format to ascertain this). The meniscus of the solution needs to completely cover the plate. You can touch the surface of the meniscus with a glass rod and drag it to the plate edge on all four sides (don't touch it with your finger - the oils from your fingers will contaminate the solution).

Heat the underside of the plate till the plate steams and continue with care. Small bubbles will form on the plate and darkish clouding may occur which will clear with continued gilding. Most of the gilding will be finished in the first minute or two, continuing for about 4 minutes will help brighten and clear the plate. What hasn't cleared after 4 minutes or so probably won't clear. Stop the heating of the plate and quench it by pouring distilled water onto it. rinse the plate throughly and dry.

Notes

  1. Pobboravsky, Irving. Study of Iodized Daguerreotype Plates, p. 42. Rochester Institute of Technology, 1972.
This page was last modified on 9 August 2011, at 12:03. This page has been accessed 14,629 times.