Have tried coating glass with commercail liquid emulsion but am experiencing difficulty in getting the emulsion to stick to the glass during development. Have tried coating with artists varnish first but this did not help. Any suggestions would be welcome. Am hoping to be able to enlarge to large sizes.
I've had success with ordinary household varnish,although the final image may take a warm cast when dry. Another variation is household primer paint which will stay on the glass but gives a light grey colour to the final image. Martin Reid of Silverprint produced an excellent book on the Alternative Processes, I cannot remember the title and cannot find my copy having just moved house but if you look at Silverprint's web site you will find it.
I have a book with a whole chapter on the preparation and coating of glass plates. I'll sit down and start translating it (it's in German, from 1904) and let you know what I find out.
-- Ole Tjugen, Luddite Elitist
Under "Common problems in the Negative Process and their Cure", Dr. Vogel covers a frightening list of things which can go wrong. Among them is "Kräuseln und Pockenbildung", which is what has happened to you...
Freely translated and excerpted from "Taschenbuch der Praktischen Photographie", XII ed., 37th-42nd thousand, by Dr. E. Vogel, Berlin 1904:
"This happens rarely during develoment, more often in fixing, even more during washing. Causes: A) Plate preparation fault, B) Use of too alkaline developer, C) Use of too concentrated or too old fixer, D) Too hot developing- or fixing bath. Cures: A) One puts the plate, after developing, for some minutes in a bath consisting of 1 l saturated Alum solution, in which one has mixed 300 ml saturated Sodium Sulfite solution and acidified with 15-20 cc Acetic Acid. B) Or one uses the Alum fixer as described on page 153. It is advantageous to cool the developer and fixer bahts. In hot climates one should always work with cooled developer and use the Alum fixer. Advantageous is also the use of the Aceton-Pyro-Developer, with which edge defects (Kräuseln) or blistering (Pocken) rarely occur."
On page 153, the Alum-Fixer:
"Many kinds of plates will get, during fixing, especially in hot weather, blisters, or the emulsion comes loose from the edges of the plate. These plates are fixed in the alum-fixer bath.
This has the following composition:
A: 1000 cc water,
64 g crystalline Sodium Sulfite,
350 g Sodium Thiosulfate
B: 1000 cc water,
80 g Potassium Alum,
28 g Potasium bisulfite
Solutions A and B are quickly mixed as soon as all ingredients are dissolved.
This bath works slower than the ordinary acid fix, but is - espacially during hot weather, much to be recommended.
The Alum-fixer bath is frequently given without the addition of Sodium Sulfite; this has the disadvantage of separating Sulfur, which sticks to the gelatine and must be removed from same with a soft brush before drying."
On the preparation of glass plates for coating:
In Dr. Vogels days, silver bromide - gelatine plates were commercially available. Most of hat he writes about plate preparation deals with colour-sensitizing premade plates, or (as a kind of "Alternative Process?) preparing your own wet collodion plates. Here's a short summary of the process for et collodion:
Plates are acidified by immersing in a mixture of equal parts concentrated Nitric acid and water for some hours. If the plates have been used before, they must be put in saturated soda for 12 hourd before this, and well washed, to remove all traces of laquer. The acidified plates are washed in lots of water while scrubbing with a brush, paying particular attentoin to the edges.
Next step is to polish the plate: The well dried plate is put in a special polishing frame with the side chosen for coating on the top. A few drops of strong ammonia solution re put on the plate, and rubbed well with a clean linen cloth; first from left to rght, then from top to bottom. It is then wiped with a clean cloth (he doesn't say whether this must be linen, too). After this breathe on the plate; if the mist is evenly and uniforly spread, the plate is ready.
Instead of the polishing, it is possible to prime the plate with a coating of chrom-gelatine:
Dissolve 1 g gelatine in 300cc hot water; after cooling add 6 cc filtered 2% Chrom-alum solution. Filter the mix twice. The primer will be usable for four to six days.
The plates are acidified and brushed as before, then covered with a sufficient amount of the primer to cover thinly and evenly, then spill over the edge. Do not reuse the runoff. A second coating is necessary; after this the plates are put vertically to dry and run off.
A: 200 g Sodium Sulfite (crystalline)
500 ml distilled water,
8 drops concentrated Sulfuric acid
14 g Pyrogallol
B: 1000 ml distilled water
50 g crystallins Sodium Carbonate
Mix 20ml A with 40ml B for use.
This is the Pyro-Soda developer.
For the Acetone-developer, 30ml A is mixed with 60ml water and 10ml acetone.
All translation errors are of my own making. If the wording or constructions seem strange, that is probably a consequence of translating from German to English through Norwegian.
The reason for the small volumes of developer is that this was meant to develop one glass plate - which does not curl or float to the surface of the tray...
I hope this helps - or at least, that it is interesting
-- Ole Tjugen, Luddite Elitist
Well from the Rockland site (assuming you are using one of their products)
"Glass and glazed ceramics only: These also require a pre-coat for adhesion, such as polyurethane, but a better alternative is a traditional photographic "subbing" solution, which fuses the photographic emulsion to the glass. Subbing works only with mineral-base materials like glass and chinaware, glazed tiles, ceramics and fired porcelain. Do not use on plastics, metals, or other materials-- use polyurethane. For a guide to the subbing procedure, see "Subbing" in Table of Contents."
And on Subbing they say -
Subbing is a traditional process for making photographic emulsions like Liquid Light stick to glass and glazed ceramics. It consists of an extremely thin layer of gelatin coated on chemically-cleaned glass. Liquid Light bonds to this thin layer, fusing with the glass so that the image seems to be virtually embedded in the glass or ceramic surface. Is it worth the extra effort?
Subbing is more time-consuming than using glossy varnish. However, the materials for the process are easily available at grocery stores, and the extra effort pays for itself with the enhanced appearance of the print and the knowlege that the emulsion will not lift off the glass or ceramic base at any time or under any conditions.
What materials can be "subbed"? Subbbing is only for dense mineral-based materials including glass, glazed ceramics, fired porcelain, natural rocks, marble, etc. On glass-resembling plastics like Lucite and Plexiglas, as well as on highly-porous materials like unglazed ceramics and plaster, do not use subbing; use glossy polyurethane varnish, following the instructions enclosed with Liquid Light.
You will need some unflavored gelatin such as Knox, sold at grocery stores, plus some powdered laundry or dishwasher detergent (do not use liquid detergent or soap, which leave a waxy film). Sprinkle one level teaspoon (approx. 3 grams) of gelatin onto the surface of one pint (450 cc's) of cold water in a saucepan. Let it stand 15 minutes to swell the gelatin, then heat with stirring until the gelatin is dissolved (140º-160º F or 45º-56º C.)
Make a strong solution of the detergent in hot water and alternately scrub and rinse the glass or ceramic (wearing rubber gloves) until the rinse water does not bead up as it drains off the glass, but leaves a uniform, nearly- invisible film. Pour some of the warm gelatin mixture onto the rinsed glass. Drain thoroughly and dry the gelatin-coated glass at least one hour in a warm place with low humidity and circulating air. (The remainder of the gelatin-water solution can be saved for up to one week under refrigeration, but should be warmed before use.)
Coating with emulsion:
The glass is now "subbed" and can be coated with emulsion. Pour a surplus of Liquid Light on the glass, tilt to spread, and pour the surplus back in the bottle. Set the glass or ceramic on a level surface with cool circulating air to speed setting and drying. The glass can be exposed while the Liquid Light is still damp or dried thoroughly and saved for future use."
Basically you end up making a gelatin plate.
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Thanks to Les Mclean, Ole Tj, Robert Kennedy for info, I now have some work to do, so must get busy. Will keep you posted. Felix.
I've started to sub glass for wet plate collodion ambrotypes and use an albumen solution to do so. One egg white in a liter is a common formula. Froth the solution and let it settle in the refrigerator for a day, then filter it for use.
Another option is to use a silane chemical. Bostick and Sullivan (an APUG sponsor) is a source for that chemical. This is probably the higher-tech and more efficient treatment.
After pouring and coating one side of the glass plate, rest the plate tilted so dust will not fall on the subbed surface as it dries.