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Varnishes and Varnishing Technique (Quinn Jacobson):
Finishing a Tintype with Renaissance Wax (Gerald Figal):
(Sorry, but YouTube auto-muted the music — “Once in a Lifetime” by The Talking Heads — I was playing in the background–those bastards!)
Tips: use a small amount of RW on a cosmetics cotton round to apply as shown. Use a separate cotton round to buff. And play The Talking Heads while doing it…
(Re)Varnishing Ambrotypes (Sergey Sergeev):
How to Finish an Ambrotype (Alex Timmermans)
How to Scan Ambrotypes and Tintypes (Alexey Alexeev):
“The Varnished Truth: The recipes and reality of tintype coatings” (Corina E. Rogge)
“The Varnished Truth” (France Scully Osterman)
Care, Handling, and Storage of Photographs (Library of Congress, courtesy of Jake Hancock)
Shellac instead of Sandarac (Gerald Figal)
Prompted by the research by Corina Rogge that revealed that tintypes in the 19th century were being varnished with shellac more often than with sandarac and have certain material advantages over sandarac, I’ve tested several shellacs, flake and pre-mixed.
If you want to mix your own (recommended), use platino (= platinum blond), the lightest available dewaxed shellac from shellac.net or Shellac Shack, or the very light “bleached” shellac sold by Kremer Pigmente because it is even lighter and would not darken the plate as much (however, it is rather expensive). Within a range, dilution (thicker or thinner) is a matter of taste and workability, but a good starting point for a pure shellac varnish is 12g shellac flakes dissolved into 100ml 95% ethanol, with 5-10ml of lavender oil added (I have personally been using a slightly thinner mix, 12g in 110ml ethanol). I did however come across one recipe in the February 21, 1891 issue of Scientific American that calls for twice the amount of shellac (12 parts shellac to 50 parts ethanol). The gloss produced might be a tad bit less shiny than sandarac and the plate darkens similar to sandarac but perhaps not quite as much. Another historical recipe calls for 9g shellac AND 0.8g sandarac in 100ml, and 3ml lavender oil. The shellac-sandarac varnish has worked well for me too. Of course you can change these volumes, but I would recommend mixing small volumes as needed because mixed shellac has a shelf-life of about 6 months while flakes kept in cool, low humidity storage (like a fridge) can last years.
To lessen the darkening effect, you need to decolorize the shellac through the process I describe below. The advantages of shellac are that is dries more quickly and harder, provides a better vapor barrier, and does not spot up if water gets on it AFTER it is cured. If you opt for bleached shellac it’s important it has not been bleached by chlorine (the usual process) or it can ruin your image over time. Kremer Pigmente bleached shellac is actually not technically “bleached” at all but simply decolorized more with activated carbon filtering.
I have found through repeated experiments that shellac pours more consistently and without issues at room temperature (about 20-22C or around 70F) rather than heating the plate and/or varnish. For details about pouring on a tintype and then drying, see this video: http://www.youtube.com/watch?v=FHoRAu64pjU
Decolorization of Shellac with Activated Carbon/Charcoal (aka ÜberSuperBlonde Shellac Varnish)
Activated carbon is well-known for its filtering attributes. It can take contaminants as well as color out of substances (for example, it’s used to refine cane sugar to whiteness, and is common in aquarium filters). It comes in powdered (PAC) and granular (GAC) forms. To do this with shellac it’s a bit tedious and messy and I’m still trying to decide if the time and effort is worth it for that full-stop lighter finish that you can get with it. Maybe. So, I’m not offering these instructions as an encouragement for all of you to do this–it’s only for those who have the patience, the necessary gear, and the desire to optimize and purify your varnish the best you can. Ideally, a centrifuge helps to cut down the filtering time, but it’s not necessary. You will need, however, a decent vacuum filtering setup and some diatomaceous earth to make a celite cake to filter through. And, of course, some activated carbon. The powdered variety in theory works better because of greater surface area, but I’ve found that granular (as can be purchased at pet shops for aquarium filters) works good enough too, but does not render the color as light as with PAC. The steps I use are as follows:
1. 1 gram of PAC per 100ml of shellac solution. It will turn jet black and you will freak out.
2. Mix and place jar of shellac w/ PAC in it in pan of hot water to heat the solution to about 110-120F.
3. Ideally, place on magnetic mixer for 30-60 minutes (or longer if you want). Or, if you don’t have a magnetic mixer stir and let sit for 30-60 minutes, stirring occasionally. In theory, the longer you let it sit, the lighter the solution will become until the carbon has reached absorption limit with the shellac. You can add more carbon, but I have never done that because there’s a point of diminishing returns where the shellac will not get lighter and all you are doing is making it more difficult to filter.
4. If you are centrifuging, divide equal amounts of solution into centrifuge tubes and spin them for 10-15 minutes at a medium setting. If not, skip to step 5.
5. Prepare your vacuum filter (= filtering flask, stopper, Buchner funnel, tubing to vacuum source such as a hand pump or electric vacuum pump). Wet with ethanol a paper filter of appropriate diameter for your Buchner funnel (mine is 90mm). Wetting the filter paper makes it stick to bottom of funnel better. Then add about a 2-4mm thick layer of diatomaceous earth on top the filter paper. Run some alcohol 2-3 times through the filter with vacuum on to get rid of dust from diatomaceous earth. Now you have a celite cake filter.
6. Clean flask and reconnect to pump. Pour shellac slowly into funnel (so as not to create craters in the celite cake). Turn vacuum pump on (or begin hand pumping). Depending on volume, pump strength, and tightness of vacuum seal on stopper (important), it might take a minute or two to filter 300ml.
7. Finally, pour the filtered shellac into a storage jar through a final cotton ball or coffee filter. It will be very clear then, but will still likely have a little very fine sediment from the celite cake and/or PAC depending on how well you prepared your filter. It usually is insignificant, but if you have a noticeable amount you might want to decant and filter one more time. The final photo here shows a before (left) and after (right). Big difference.
