perceptol formula?

Discussion in 'Darkroom Developing and Printing' started by Larry, Jul 24, 2008.

  1. Larry

    Larry Guest

    Does anyone out there have the perceptol formula? If you do, could
    you send to my e-mail. thanks....

    Larry
     
    Larry, Jul 24, 2008
    #1
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  2. 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, Jul 25, 2008
    #2
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  3. What is the patent number?
    I have seen some Kodak patents for fine-grain developers containin
    sodium and ammonium chloride and a couple of patents for anti-stai
    agents that reduce or eliminate dichroic fog
     
    Keith Tapscott., Jul 25, 2008
    #3
  4. Edgar Hyman`s Microdol substitute is 5 grams of Metol, 100 grams o
    sodium sulphite, anhydrous and 30 grams of sodium chloride per litre o
    stock solution although I don`t know how close that is to Kodak`
    Microdol-X or Ilford`s Perceptol or the exact additives to th
    commercially sold products
     
    Keith Tapscott., Jul 25, 2008
    #4
  5. "Keith Tapscott." <>
    wrote in message
    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, Jul 26, 2008
    #5
  6. including that one.
    http://www.google.com/patent
     
    Keith Tapscott., Jul 27, 2008
    #6
  7. "Keith Tapscott." <>
    wrote in message
    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, Jul 27, 2008
    #7

  8. 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, Jul 27, 2008
    #8
  9. 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, Jul 27, 2008
    #9
  10. They had a group of people reading the
    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, Jul 27, 2008
    #10
  11. Larry

    Helge Nareid Guest

    Well, there are a few good search engines for searching patents. Given
    international patent law, patent applications have to be made public
    after a set period (normally 18 months). The best site for patent
    searches I've found to date is

    http://www.freepatentsonline.com/

    By the way, have a look at their frivolous patent page

    http://www.freepatentsonline.com/crazy.html

    Anybody who has ever amused a cat using a laser pointer or even
    thrown a stick for a dog should be afraid - very afraid ... ;-)

    - The Horrible Helge
     
    Helge Nareid, Jul 27, 2008
    #11
  12. Well, considering the recent Los Angeles weather, I
    ought to be getting rich.
     
    Richard Knoppow, Jul 27, 2008
    #12
  13. Well, there are a few good search engines for searching
    patents. Given
    international patent law, patent applications have to be
    made public
    after a set period (normally 18 months). The best site for
    patent
    searches I've found to date is

    http://www.freepatentsonline.com/

    By the way, have a look at their frivolous patent page

    http://www.freepatentsonline.com/crazy.html

    Anybody who has ever amused a cat using a laser pointer or
    even
    thrown a stick for a dog should be afraid - very afraid ...
    ;-)

    - The Horrible Helge
    --
    - Helge Nareid
    Nordmann i utlendighet, Aberdeen, Scotland
    For e-mail, please refer to my website.
    Website: http://www.nareid-web.me.uk/

    Its good to hear from you Helge and to know that you
    still follow this group. Google Patents works only for US
    patents. I will try the link you gave for others. Most of
    the patents I look for are for historical research, the
    sites I've tried for European and English patents do not go
    back far enough.
    At one time there was a patents column in the _Journal
    of the Audio Engineering Society_ where the reviewer often
    pointed up some frivolous patents. It is quite surprizing
    what can get by the patent examiners. For a long time, and
    maybe still, there was a racket in nuicance law suits
    against large companies for patent infringment. May
    companies chose to simply buy off the plaintiff since it was
    cheaper than defending the case in court even if the case
    had no merit.
    Learning to read patentese is necessary since the
    stilted legal language of patents is often very confusing.
    Of course, patents are _legal_ not technical or scientific
    documents and are often writen to be somewhat indefinite.
    Kodak's patents are generally well written and explicit and
    are very often useful to read. Its evident from them that
    they possessed a lot more technology than they seem to have
    applied although its very hard sometimes to know which
    patents have been used commercially and which were applied
    for on the general principle of patenting any patentable
    development of a research facility.
    Another example is the patents cited by Harry Olson,
    RCA's top acoustic researcher, in his writings, all are
    necessary to look up because a lot of "secrets" are in them.
     
    Richard Knoppow, Jul 27, 2008
    #13
  14. That depends upon your point of view. Just because something was patented
    in 1945 does not mean that it's not still in use, or that it can not be
    improved.

    Let's say just for sake of discussion, you figure out that adding mango juice
    to microdol X makes it work better. It actually might, it contains salt
    and vitamin C, both have which have been mentioned here as improving film
    developers.

    If you could prove that the combination of two produces an improved product
    and you might be able to sell it. If you sold it, or the idea, you would
    want to patent it to prevent others selling it.

    Personally I doubt that an improved developer formula would sell enough
    to cover the cost of a patent, but you never know. :)

    As I said, I have no idea what Google does with their data mining, if they
    data mine patent searchs at all, but since they data mine regular searches,
    email, etc. it is quite likely.

    People have postulated having a free prior art or patent search website and
    have the results of data mining examined by a group of low paid PhD's in
    India or China. The ideas that seemed marketable could be turned into
    U.S. provisional patent applications in a mater of days and then sold,
    possibly before the original searcher read all the results of their search.

    IBM certainly did the data mining, but their focus was limited only to
    items that fit their business. AFAIK, they have never claimed to have
    succeded in data mining an idea and bringing the product to market, but
    I'm not sure that is something they would admit.

    Geoff.
     
    Geoffrey S. Mendelson, Jul 28, 2008
    #14
  15. Larry

    Helge Nareid Guest

    [... big snip ...]
    Hi there Richard. I never really left this group, but since that I
    don't do any darkroom work these days - for various reasons but mainly
    because I don't have my own darkroom any longer, I've mainly been
    lurking.

    I should have paid more attention to your original remark. As you will
    be well aware, there is a significant cost to scanning pre-digital
    patent documents and converting them to searchable text.

    Given that most patent search engines are focused on current
    technology, the support for older patents can be somewhat sketchy.

    However, just to test the facility I did a simple inventor test for
    our old "friend" Charles E. K. Mees (head of research at Eastman Kodak
    from 1912 to 1955, for those with less encyclopediac knowledge than
    Richard). The oldest patent I found on freepatentsonline.com with him
    listed as an inventor is United States Patent 1396770, dating back to
    1921. I also checked out the best European search site I know of,
    which is the semi-official site of the European patent offices -
    http://gb.espacenet.com/. It came back with Canadian patent CA368787
    from 1937.

    I will admit that I am actually quite impressed, but I appreciate that
    it may not suffice for some of the historical research that you do.

    I have found that people working with patents share a trait that I
    have long come to appreciate in librarians - they never query your
    interest in an esoteric or outdated subject, but just do their best to
    help you - and their best can be quite impressive (but it can also be
    quite expensive).

    My own experience with patent searches have been in relation to more
    modern patents, but I have on occassions had the experience of working
    with professionals in the patent field using the tools they have at
    their disposal. These tools have incredible power, but also have a
    significant cost - well beyond what amateur researchers can afford.
     
    Helge Nareid, Jul 28, 2008
    #15
  16. [... big snip ...]
    Hi there Richard. I never really left this group, but since
    that I
    don't do any darkroom work these days - for various reasons
    but mainly
    because I don't have my own darkroom any longer, I've mainly
    been
    lurking.

    I should have paid more attention to your original remark.
    As you will
    be well aware, there is a significant cost to scanning
    pre-digital
    patent documents and converting them to searchable text.

    Given that most patent search engines are focused on current
    technology, the support for older patents can be somewhat
    sketchy.

    However, just to test the facility I did a simple inventor
    test for
    our old "friend" Charles E. K. Mees (head of research at
    Eastman Kodak
    from 1912 to 1955, for those with less encyclopediac
    knowledge than
    Richard). The oldest patent I found on freepatentsonline.com
    with him
    listed as an inventor is United States Patent 1396770,
    dating back to
    1921. I also checked out the best European search site I
    know of,
    which is the semi-official site of the European patent
    offices -
    http://gb.espacenet.com/. It came back with Canadian patent
    CA368787
    from 1937.

    I will admit that I am actually quite impressed, but I
    appreciate that
    it may not suffice for some of the historical research that
    you do.

    I have found that people working with patents share a trait
    that I
    have long come to appreciate in librarians - they never
    query your
    interest in an esoteric or outdated subject, but just do
    their best to
    help you - and their best can be quite impressive (but it
    can also be
    quite expensive).

    My own experience with patent searches have been in relation
    to more
    modern patents, but I have on occassions had the experience
    of working
    with professionals in the patent field using the tools they
    have at
    their disposal. These tools have incredible power, but also
    have a
    significant cost - well beyond what amateur researchers can
    afford.
    --
    - Helge Nareid
    Nordmann i utlendighet, Aberdeen, Scotland
    For e-mail, please refer to my website.
    Website: http://www.nareid-web.me.uk/

    I don't remember what I came up with searching for Mees
    but searches for some other Kodak researchers like Richard
    Henn, John Crabtree, etc, will get loads. Crabtree was head
    of the chemical division and seems to have gotten his name
    on a lot of patents from research done under his direction
    but likely not by him personally. Names of Kodak optical
    designers are familiar to you and any of them will come up
    with numerous patents. Rudolf Kingslake does not seem to
    have followed Crabtree's pattern of having his name on
    patents from his department. Try George Aklin for example,
    but there are others.
    I search out of simple (or maybe not so simple)
    curiousity. I am interested in the history of technology
    generally and have found myself collecting patents for
    photographic chemistry, optics, steam locomotives, several
    areas of electronics, etc. Patents, of course, multiply even
    as you watch so one can go on forever following up
    citations: sometimes they are more interesting than the
    patents.
    A good, but expensive, resource for optical patents is a
    computer program called Lensview, compiled by Brian
    Caldwell. I was given it as a present and refer to it often.
    It includes the Zeiss Index, which no doubt you are familiar
    with.
    This should really be personal e-mail but let it all
    hang out as they said in my youth, its probably totally
    boring to all but us anyway.
     
    Richard Knoppow, Jul 29, 2008
    #16
  17. Richard Knoppow wrote:

    Strange: your e-mailer seems to not understand the "-- " convention,
    stripping everything after it as signature. But mine does, so when I tried
    to reply, nothing was there.
    I am interested in them too. There is a very old patent, undoubtedly from
    the 19th century, for a means of clearing the track of livestock. It
    consisted of a pipe from the steam dome to the front of the locomotive where
    there was a nozzle. There was a valve in there too. When the cow would not
    get off the track, the engineer opened the valve and motivated the cow to
    get off the track.

    Another one was to prevent collisions on single track lines. It consisted of
    an inclined plane from the track up over the locomotive, tracks along the
    tops of all the cars, and a plane down at the other end of the train. On
    encountering one another, one train would pass over the other. You can
    imagine the difficulties with this.

    Both patents were granted. In those days, I do not believe you had to reduce
    the patented idea to practice. The first one might have worked, sometimes,
    maybe. The second is preposterous.
     
    Jean-David Beyer, Jul 29, 2008
    #17
  18. Yes, I noticed the same problem; Richard's reply ended up as part of the
    previous poster's sig, which of course is supposed to be stripped out of
    the reply.

    Richard: you may have ended up typing after their sig, in which case you
    should simply more your cursor elsewhere before you compose your reply.

    In any case, for those who missed it, here's Richard's reply:

    --
    "Wikipedia ... it reminds me ... of dogs barking idiotically through
    endless nights. It is so bad that a sort of grandeur creeps into it.
    It drags itself out of the dark abyss of pish, and crawls insanely up
    the topmost pinnacle of posh. It is rumble and bumble. It is flap and
    doodle. It is balder and dash."

    - With apologies to H. L. Mencken
     
    David Nebenzahl, Jul 29, 2008
    #18
  19. Larry

    Lloyd Erlick Guest




    July 31, 2008, from Lloyd Erlick,

    It would be boring if you took it off-list.

    I'm sure we all have various reasons for
    hanging around on this particular discussion
    forum. Part of mine is to give my mind a
    break from the daily pressures (not that
    they're so onerous, but wot th' 'ell ...).

    I'm pleased you let the rest of us listen in
    on your conversations.

    regards,
    --le
    ________________________________
    Lloyd Erlick Portraits, Toronto.
    website: www.heylloyd.com
    telephone: 416-686-0326
    email:
    ________________________________
    --
     
    Lloyd Erlick, Jul 31, 2008
    #19
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