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perceptol formula?
"Larry" wrote in message ... Does anyone out there have the perceptol formula? If you do, could you send to my e-mail. thanks.... Larry The formula for Perceptol is proprietary. Perceptol is evidently very similar, if not identical, to Kodak Microdol-X. I have somewhere a patent which I believe is for Microdol but will have to search for it. Both are low pH developers which rely on sodium chloride (common table salt) as the fine grain agent. Microdol-X evidently contains a silver sequestering agent to prevent dichroic fog, otherwise a problem for this type of developer. Its very likely Perceptol has the same thing. My experience with Perceptol is that it produces very clean negatives. If I can find my guess at the Microdol formula I will post it but both of these developers are similar to Kodak D-23 with about 25 grams of sodium chloride added. I have no idea of what the sequestering agent is, possibly a mercaptan but Kodak has many patents for anti-silvering agents an any one of them could be the X in Microdol-X. -- --- Richard Knoppow Los Angeles, CA, USA |
#2
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Quote:
I have seen some Kodak patents for fine-grain developers containing sodium and ammonium chloride and a couple of patents for anti-stain agents that reduce or eliminate dichroic fog. |
#3
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Edgar Hyman`s Microdol substitute is 5 grams of Metol, 100 grams of sodium sulphite, anhydrous and 30 grams of sodium chloride per litre of stock solution although I don`t know how close that is to Kodak`s Microdol-X or Ilford`s Perceptol or the exact additives to the commercially sold products.
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#4
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perceptol formula?
"Keith Tapscott." wrote in message ... Edgar Hyman`s Microdol substitute is 5 grams of Metol, 100 grams of sodium sulphite, anhydrous and 30 grams of sodium chloride per litre of stock solution although I don`t know how close that is to Kodak`s Microdol-X or Ilford`s Perceptol or the exact additives to the commercially sold products. -- Keith Tapscott. One patent covering the Microdol type developer is: USP 2466423 issued to John I. Crabtree and Richard Henn and assigned to Kodak. The patent has some discussion of the problem of silver fog in fine grain developers and suggests some compounds for suppressing it. There are sample formulas for both liquid concentrate and powdered developers. The simplest is copied below but I suggest reading the patent for a greater understanding of what the inventors were trying to do. Microdol _type_ developer Water to make 1 liter Metol 5.0 grams Sodium sulfite, anhydrous 100.0 grams Ethylene diamine sulfate 12.0 grams Sodium metaborate 4.0 grams Potassium bromide 0.25 grams Sodium chloride 20.0 grams The patent is dated 1945 so its about right for the original Microdol. The X version was released a couple of years later. Presumably the X indicates an improvment, probably in the form of a better silver sequestering agent. Kodak holds many patents on various sequestering agents, only a couple are mentioned in the above patent. -- --- Richard Knoppow Los Angeles, CA, USA |
#5
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Quote:
http://www.google.com/patents |
#6
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Another one here describes the use of antistain agents, although I am told that these have long been superceded.
http://www.google.com/patents?id=vHF...ain+Developers |
#7
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perceptol formula?
"Keith Tapscott." wrote in message ... Richard Knoppow;744145 Wrote: One patent covering the Microdol type developer is: USP 2466423 issued to John I. Crabtree and Richard Henn and assigned to Kodak. The patent has some discussion of the problem of silver fog in fine grain developers and suggests some compounds for suppressing it. There are sample formulas for both liquid concentrate and powdered developers. The simplest is copied below but I suggest reading the patent for a greater understanding of what the inventors were trying to do. Microdol _type_ developer Water to make 1 liter Metol 5.0 grams Sodium sulfite, anhydrous 100.0 grams Ethylene diamine sulfate 12.0 grams Sodium metaborate 4.0 grams Potassium bromide 0.25 grams Sodium chloride 20.0 grams The patent is dated 1945 so its about right for the original Microdol. The X version was released a couple of years later. Presumably the X indicates an improvment, probably in the form of a better silver sequestering agent. Kodak holds many patents on various sequestering agents, only a couple are mentioned in the above patent. -- --- Richard Knoppow Los Angeles, CA, USA There are some other similar patents for fine-grain developers including that one. http://www.google.com/patents -- Keith Tapscott. Thats where I found it, probably doing a name search for Richard Henn. Google Patents is an excellent research tool since you can do complete text searches on any U.S. patent ever issued and all are available directly as PDFs. The U.S. Patent Office site allows text searches only for patents issued from 1976 and all patents are downloaded as page-by-pate FAX Tiff files. Its easy enough to convert them to a single PDF but Google does it for you. Each patent will give you some clue as to other searches. Its never ending and a very great time sink. -- --- Richard Knoppow Los Angeles, CA, USA |
#8
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perceptol formula?
Richard Knoppow wrote:
Thats where I found it, probably doing a name search for Richard Henn. Google Patents is an excellent research tool since you can do complete text searches on any U.S. patent ever issued and all are available directly as PDFs. Before Google Patents and the USPTO web site, IBM had an on-line patent search web site. If you read the fine print, they told you that they data-mined the queries. They had a group of people reading the results of the data mining and the best ideas were presented to IBM managment for evaulation and possible development as IBM products. Since Google data-mines everything they "give" you, I would be very careful about what I search there. I'm not saying they will take your ideas, but who knows. It may also be construed as publication in a court of law. Geoff. -- Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM |
#9
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perceptol formula?
"Geoffrey S. Mendelson" wrote in message ... Richard Knoppow wrote: Thats where I found it, probably doing a name search for Richard Henn. Google Patents is an excellent research tool since you can do complete text searches on any U.S. patent ever issued and all are available directly as PDFs. Before Google Patents and the USPTO web site, IBM had an on-line patent search web site. If you read the fine print, they told you that they data-mined the queries. They had a group of people reading the results of the data mining and the best ideas were presented to IBM managment for evaulation and possible development as IBM products. Since Google data-mines everything they "give" you, I would be very careful about what I search there. I'm not saying they will take your ideas, but who knows. It may also be construed as publication in a court of law. Geoff. -- Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM Well, first of all I am searching to satisfy my curiousity. Secondly, most of the patents I look at are very old, long expired, and not useful for anyone trying to guess what new, novel, and useful things I am inventing. I doubt if anyone doing serious patent searches for the purpose of, say, finding out if something is prior art, would use Google and one can not use the USPTO site for that except for a fee: the free searching has a limit. -- --- Richard Knoppow Los Angeles, CA, USA WB6KBL |
#10
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perceptol formula?
They had a group of people reading the
results of the data mining and the best ideas were presented to IBM managment for evaulation and possible development as IBM products. That doesn't happen. IBM is full of people promoting their _own_ ideas, no one there is about to promote someone else's. Inspiration is worthless, it's the perspiration that is worth something. -- Nicholas O. Lindan, Cleveland, Ohio Darkroom Automation: F-Stop Timers, Enlarging Meters http://www.darkroomautomation.com/index2.htm n o lindan at ix dot netcom dot com |
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