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#11
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Tmax & D-76
"Nicholas O. Lindan" wrote in message m... "Richard Knoppow" wrote The line about T-Max being as fine grained in Microdol-X as Technical Pan in Technidol is from me. HA! If I could get Google to search rec.photo.darkroom - I am sure I was pointing this out as early as ... * * * * Perceptol - from the MSDS information - doesn't really look a whole lot like Microdol-X Part A: Metol Part B S. Sulfite S. Bromide S. Tripolyphosphate (STPP) The STPP is a water softening agent in this application (among it's other uses it adds weight to seafood by making it retain water). I don't know if there is a dichroic fog inhibitor or if the bromide takes care of it. I guess P. Bromide could be a fine-grain agent, but I would wonder about its effect on shadow detail. The only film developer w/ bromide TIKO (WTEO Perceptol) is D-96, used by the motion picture industry. One rather whacked-out developer in the Microdol-X vein is Rollei RLS (LP Cube XS) that is made from Metol Ammonium Chloride without the s. sulfite (if the MSDS can be believed). -- Nicholas O. Lindan, Cleveland, Ohio Darkroom Automation: F-Stop Timers, Enlarging Meters http://www.darkroomautomation.com/da-main.htm n o lindan at ix dot netcom dot com Be careful! The MSDS you have for Perceptol is an old one and in error. I wrote them about the sodium bromide, its suppsed to be sodium chloride. Its possible that Microdol-X has ammonium chloride in it, I think the cation may not be important. But there are often several versions of MSDS around. Also, they don't show all the ingredients, only those deemed to be hazardous and sometimes not even those if present in very small quantity. For instance both T-Max and T-Max RS are Phenidone developers but no mention of it was made in their MSDS for years. Many packaged developers have some sort of sequestering agent or agents in them to control impurities in the water, mostly magnesium and calcium carbonates, the most common "hardness" in water and sometimes also trace metals like iron. I don't have an actual formula for Microdol/Perceptol but it appears to contain about 15 or 20 grams of sodium chloride per liter of working solution, otherwise similar to D-20. I am pretty sure the X in Microdol-X is a silver sequestering agent, perhaps a mercaptan, to prevent dichroic fog. I never had any problem with this from Perceptol so perhaps it too has some anti-silvering agent in it. Kodak has a ton of patents for anti-silvering agents, who knows which were actually used and where since they can also be added to emulsions. -- Richard Knoppow Los Angeles, CA, USA |
#12
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Tmax & D-76
"Richard Knoppow" wrote
The line about T-Max being as fine grained in Microdol-X as Technical Pan in Technidol is from me. HA! If I could get Google to search rec.photo.darkroom - I am sure I was pointing this out as early as ... * * * * Perceptol - from the MSDS information - doesn't really look a whole lot like Microdol-X Part A: Metol Part B S. Sulfite S. Bromide S. Tripolyphosphate (STPP) The STPP is a water softening agent in this application (among it's other uses it adds weight to seafood by making it retain water). I don't know if there is a dichroic fog inhibitor or if the bromide takes care of it. I guess P. Bromide could be a fine-grain agent, but I would wonder about its effect on shadow detail. The only film developer w/ bromide TIKO (WTEO Perceptol) is D-96, used by the motion picture industry. One rather whacked-out developer in the Microdol-X vein is Rollei RLS (LP Cube XS) that is made from Metol Ammonium Chloride without the s. sulfite (if the MSDS can be believed). -- Nicholas O. Lindan, Cleveland, Ohio Darkroom Automation: F-Stop Timers, Enlarging Meters http://www.darkroomautomation.com/da-main.htm n o lindan at ix dot netcom dot com |
#13
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Tmax & D-76
"Peter Irwin" wrote
This matches my experience with TMX in Microdol-X. Grain is amazingly fine, actual resolution is very good, but it just didn't look /sharp/. I used TMX/M-X for shooting resolution targets a few years ago when I ran out of Tech Pan. I found the combination has the same resolution with a high contrast target as Tech Pan. Microdol-X does not reduce resolution. That it is a 'solvent developer' is an urban legend - it has no more S. Sulfite in it than D-76. Often systems that have lower resolution look sharper. I am not interested in the appearance of detail, but only in real detail. 'Acutance' and touted 'edge effects' are, in my book, vile concepts. -- Nicholas O. Lindan, Cleveland, Ohio Darkroom Automation: F-Stop Timers, Enlarging Meters http://www.darkroomautomation.com/da-main.htm n o lindan at ix dot netcom dot com |
#15
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Tmax & D-76
"Richard Knoppow" wrote
The MSDS you have for Perceptol is an old one and in error. I wrote them about the sodium bromide, its suppsed to be sodium chloride. Ah, now that makes a lot more sense. When Kodak announced the discontinuation of Microdol-X I looked into Perceptol, came upon the erroneous MSDS and promptly bought 10 bags of M-X. I have tried the home-brew Microdol - D-23 with a 30 (?) gm/l dollop of pure NaCl and it silvers badly when used with TMax films. If Perceptol works with TMax/Delta then it more than likely has an anti-silvering agent in it. Hmm, anti-silvering - anti-Ag'ing - Anti-Aging. I wonder if one could sell the stuff on the back pages of the National Enquirer. Proven Anti-Aging formula ... Might help all those people poisoning themselves with colloidal silver. -- Nicholas O. Lindan, Cleveland, Ohio Darkroom Automation: F-Stop Timers, Enlarging Meters http://www.darkroomautomation.com/da-main.htm n o lindan at ix dot netcom dot com |
#16
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Quote:
I don't use Perceptol much these days. |
#17
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The only difference I can see from the MSDS for Microdol-X and Perceptol, is that Kodak list boric oxide (B2O3) as a component. Both developers list sodium chloride as constituents.
A former Kodak pundit has mentioned on a popular photo-forum, that Kodak encapsulate the developing agents with a special coating to prevent them from reacting with the other constituents in the single-powder compounds. I am wondering if that special component is the boric oxide (boric anhydride) that Kodak mention in their MSDS's. Ilford do similar to their P.Q. powder developers by adding a pinch of sodium metabisuphite in Part 'A' of Microphen and Bromophen, but not in ID-11 or Perceptol, as Metol is already slightly acidic. Ilford information sheet P 10.5 FINE GRAIN DEVELOPMENT: Shows that ID-11 and ID-2 can be modified to produce finer grain by adding ammonium-chloride. Use 40 grams for each litre of stock ID-11 and 10 grams for each litre of working strength ID-2 (1+2). |
#18
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Back on topic, using films like T-Max 100, Delta 100 and Acros 100 in a true fine-grain developer of the Microdol type, will yield grain as fine as can be expected without switching to special micro-fine grained B&W films which require specially formulated low contrast developers.
The down side, is some loss of effective film speed and acuity. I prefer my negatives with a bit more sharpness over the finest grain, so it's D-76 1+1 for me. |
#19
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Tmax & D-76
"Keith Tapscott." wrote in message ... The only difference I can see from the MSDS for Microdol-X and Perceptol, is that Kodak list boric oxide (B2O3) as a component. Both developers list sodium chloride as constituents. A former Kodak pundit has mentioned on a popular photo-forum, that Kodak encapsulate the developing agents with a special coating to prevent them from reacting with the other constituents in the single-powder compounds. I am wondering if that special component is the boric oxide (boric anhydride) that Kodak mention in their MSDS's. Ilford do similar to their P.Q. powder developers by adding a pinch of sodium metabisuphite in Part 'A' of Microphen and Bromophen, but not in ID-11 or Perceptol, as Metol is already slightly acidic. Ilford information sheet P 10.5 FINE GRAIN DEVELOPMENT: Shows that ID-11 and ID-2 can be modified to produce finer grain by adding ammonium-chloride. Use 40 grams for each litre of stock ID-11 and 10 grams for each litre of working strength ID-2 (1+2). -- Keith Tapscott. Kodak uses some odd chemical names for more familiar stuff in their MSDS. Kodak also has a bunch of patents on methods of combining chemicals for use in powder formulas, I have no idea of which ones were actually used commercially. AFAIK, boric anhydride is becomes boric acid in solution and suggests that there is a buffer combination there similar to the one in D-76d which uses borax and boric acid. Those familiar with the art (patent speak) know that its usual in published formulas to list the chemicals in the order in which they are to be dissolved. When a developer contains Metol it is dissolved first, or at least before the sulfite. The reason is that Metol does not dissolve in a fairly strong sulfite solution. In the past it was common for packaged developers to come in two parts, the first contained the Metol and was dissolved first, the second contained the remainder of the ingredients. Kodak has a method of treating the chemicals in packaged developers so that all can be combined at once. Note that packaged D-76 and Dektol consist of a single container. I don't know exactly what they do. One reads occasional complaints about the difficulty of dissolving these packaged developers without having a residue of undissolved crystals. I have wondered if this problem is the result of this treatment. BTW, I've found that the problem is at least minimised by keeping the solution hot until solution is complete. Kodak is reportedly discontinuing D-76, Microdol-X, and Kodak Hypo Clearing Agent. Ilford makes similar if not identical products but Kodak originated all of these and I can't help but wonder if the Ilford versions are really identical. For one thing the MSDS for ID-11 indicates its not buffered. D-76 has a problem with increasing activity as it ages which is cured by the buffering found in the Kodak version. Perceptol seems to work very well and I routinely use it for T-Max 100 and have used it for several other films. I am not sure what is in Ilford wash aid but its seems to be the same as KHCA, a buffered solution of sodium sulfite. Kodak adds two sequestering agents to control deposition of aluminum compounds from the hardener and metallic carbonates in the water. I wonder if Ilford adds these since they do not use hardener in their fixing baths. Unfortunately we live in a age of super-giant corporations, that way because it is "more efficient" but, in fact they are not very efficient and are incapable of catering to medium or small markets profitably, something that smaller and more specialized businesses _are_ able to do. Being big is not always an advantage. Years ago I came across a very interesting paper called "On Being the Right Size". I can't remember the author, it was in an anthology of papers on either mathematics or physics published by _Scientific American_ magazine. Maybe a web search would find it. -- -- Richard Knoppow Los Angeles, CA, USA |
#20
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Tmax & D-76
Richard Knoppow wrote:
Being big is not always an advantage. Years ago I came across a very interesting paper called "On Being the Right Size". I can't remember the author, it was in an anthology of papers on either mathematics or physics published by _Scientific American_ magazine. Maybe a web search would find it. It can be found in The World of Mathematics, Volume 2, pages 952 ff. "On Being the Right Size" by J.B.S. Haldane. Haldane, J. B. S. (March 1926). "On Being the Right Size". Harper's Magazine. -- .~. Jean-David Beyer Registered Linux User 85642. /V\ PGP-Key: 9A2FC99A Registered Machine 241939. /( )\ Shrewsbury, New Jersey http://counter.li.org ^^-^^ 15:10:01 up 11 days, 18:02, 3 users, load average: 5.12, 4.86, 4.80 |
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