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Reversal Formulas, Color Formulas
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| found at the following URL --
http://www.telusplanet.net/public/sam3d/stereostuff/samrev1.htm
Sam's Technical Pan Reversal Variation |
| This conversation took place on rec.photo.darkroom on March 10, 2003: |
| "Peter Chant" <pete@petezilla.co.uk> wrote in message news:b4asdh$o4q$1@phoenix.fire... > I've considered taking black and white slides. Agfa Scala is one option > but I have noticed in a book reversal processing of b&w film, my question > is where can I get the chemicals? > > The process involves processing in a MQ developer, I've noticed PQ on > Jessops website, then bleaching in a mixture of sodium bichromate and > sulfuric acid. This is followed by clearing in a solution of > sodium sulfite and sodium hydroxide, fogging and then developing and fixing > as normal (using MQ developer). > > Where can I get MQ developer? > Where can I get the sodium bichromate and sulphuric acid, what is it sold as? > Ditto for sodium sulphite and sodium hydroxide? > > I suspect that if I were really keen I could track down lab suppliers etc, > but surely they can be bought from suitable photographic suppliers? > Am I missing some common trade names? > > > Pete > Most standard developers are M-Q types. Phenidone is usedinstead of metol in some developers since it is less toxic and has some speed advantage. This makes no difference in reversal processing. Reversal processing uses a very active first developer in comparison to normal negative developing. These developers resemble those used for printing paper. In fact, the same developers can be used. Typically, some halide solvent is added, often a thiocyanate or even just hypo (thiosulfate). This insures clearing out of the very finest grains of silver halide which are so insensitive to light that they are not made developable by even gross overexposure. The solvent increases the speed of the film as a reversal film and insures clear highlights in the reversed image. The amount of solvent varies with the film and must be found experimentally. The most common bleach is a mixture of potassium dichromate and sulfuric acid. Both are considered hazardous materials now so are not so easy to get. Both must be handled with considerable care. I would suggest at least reading a book on elementary chemistry to learn basic laboratory safety procedures before using these chemicals. This bleach removes the metallic silver produced by the first development but leaves the undeveloped silver halide in place. The chromic acid bleach leaves a strong yellow stain which is removed by treating the film in a solution of sodium sulfite or metabisulfite. The film is then washed to remove the sulfite and reaction products. It is then exposed to a fairly strong light to fog the remaining silver halide and given a second development in a strong developer, essentially a print developer, not much different than the first developer, but without the halide solvent. The film is simply developed until all the remaining silver is developed. The film shold then be fixed. While in principle all the halide should be converted to metallic silver, in practice some very fine particles may have survived and wil eventually degrade the image if not removed by fixing. The film is then washed and your through. Ilford has a procedure for reversal development using their standard print developer on its web site. While they use Bromophen, a Phenidone print developer, a metol developer like Kodak Dektol will work as well. Ilford gives formulas and times for its own films but they will work for other films although the first development time may have to be adjusted. Richard Knoppow |
| ILFOCHROME DIVIDED DEVELOPER:
posted on rec.photo.darkroom by lrkalajainenATsuscom-maineDOTnet in
October 2004:
"As Claudio requested and I
promised, here is a formula I've used |
| From Dave Morel in the UK comes the following: |
| In message <39ScnQO3AtO-g6SjXTWcpA@comcast.com>
you wrote: > http://www.tech-diy.com/BWtransparencies.htm > > "PhotoMan" <jobin02ebay@hotmail.com> wrote in message > news:WS_Z9.50600$G61.496301@weber.videotron.net... > > I am looking for formulas for making transparency from T-Max100. The kodak > > kit is very expensive. > > Any suggestion? > > > > > > Hi John Sorry to take a few days replying to this but I could not find where I had stored the info. A few years ago Paul Moshay had reported that he had a set of formulae for TMax. I asked him to send them and I will tag his reply on to this. They had been published in an American Photo Magazine. I have tried these and was very impressed with the results. They were the best b/w slides I had ever had. I did find that I needed to change his first development time. His suggested time gave me very dark slides. I found that an extension of the time to 12 mins @70degree C gave me better results than downrating TMax. I also found that the formulae worked well on other films but the clarity of TMax's base gave it the edge. Here is what Paul sent to me. ------------------------------------------------------ Hi Dave, Tmax is easy to reverse with this formula and a heck of a lot less expensive than Kodaks kit. Here is the formula, let me know how it works out for you. Best to you, Paul Moshay REVERSAL DEVELOPMENT OF TMAX FILM This is the formula I used for reversal of TMax 100 and Tmax 400 film. It worked well for both 35mm and 120 films. I found this in the Mar/Apr 1988 issue of Darkroom & Creative Camera Techniques. 1: FIRST DEVELOPER Water at 125 deg. 750 cc Metol 2 grams Sodium Sulfite, Anhydrous 100 grams Hydroquinone 5 grams Sodium Carbonate, Monohydrate 60 grams Sodium Thiosulfate, Pentahydrate 16 grams Potassium Bromide 4 grams Cold water to make 1 liter Develop 10 min @ 68deg - Constant gentle agitation. Use once and discard. NOTE: If you do not wish to mix this, you may use Kodak D76 or Ilford ID11+ Adding: 15 grams Sodium Carbonate 4 grams Sodium Thiosulfate 1 gram Potassium Bromide Per 250ml for each roll 2: WASH 2 Minutes - Running water. 3: BLEACH Potassium Dichromate 9.5 grams Sulphuric Acid 12 cc Agitate 3 minutes. After 3 minutes the light may be turned on and the remainder of the process can be done in white light. 4: WASH IN RUNNING WATER 3 MINUTES. 5: CLEARING BATH Water 1000 cc Sodium Sulfite, Desiccated 50 grams Agitate for 1 minute. 6: RINSE IN WATER 2 MINUTES 7: REEXPOSURE TO LIGHT. Expose film to white light of a Photoflood bulb in a reflector at 5 feet for 2 minutes. Film may remain on the reel. Rotate reel to insure complete coverage of film by light. Do not use sunlight. 8: REDEVELOPMENT, Second Developer Dektol 1:2 for 3 minutes 9: WASH 3 MINUTES. 10: FIX 5 minutes in regular hardening fixer. 11: HYPO CLEAR, WASH and DRY as usual. NOTES: The time for First Development should be thought of as a starting point. The First Development is the most critical part, so try to keep all the variables, time and temprature, as constant as possible. Expose and develop a test roll or two of film to arrive at a time and exposure index that is suitable for your system. Overexposure will result in thin slides lacking in density, and underexposure will do the opposite. TMax 100 and TMax 400 can be rated at about its full speed but will have to be customized for your conditions. In order to obtain Sepia toned slides, instead of the Dektol, the Second Developer may be composed of 2 grams per liter of SODIUM SULFIDE. (Not Sulfite.) ----------------------------------------------- I hope this helps All the best Dave -- Dave Morrell Middlesbrough (UK) |