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  1. #31
    Alex Hawley's Avatar
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    Quote Originally Posted by Photo Engineer View Post
    Alex;

    It works very well, but there is image spread unfortunately. The saving grace is that the spread from the film to the paper is near what the eye can detect at normal viewing distance.

    PE
    Must be. I sure can't see any anomalies.
    Semper Fi & God Bless America
    My Photography Blog

  2. #32

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    Quote Originally Posted by Photo Engineer View Post
    I have found two methods in the literature I have on making black and yellow silver colloids.
    Would you be kind enough to start a new thread where you give more detail on the methods you found. It may be useful. I think I noticed some patents (for t-grains?) where they were adding Carey Lea silver during the emulsification steps at a certain point in the process.

  3. #33
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    Kirk,

    I'll start the new thread with a link to a very interesting background article. I have no idea how to make colloidal silver, but the whole historical aspect of it is fascinating.

    Denise

  4. #34
    Photo Engineer's Avatar
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    A myth put to rest

    Well, today was one of our irregular photo engineers lunches at George Eastman House. One of the topics was the popular myth that Land used a Kodak emulsion formula (variously Pan X or Plus X depending on source).

    Land, in a note somewhere, says that he originally used Kodak sheet film (Pan X) to demonstrate the feasibility of instant B&W imaging. Then he went on to develop his OWN emulsions for his product lineup.

    In no way is any Land formula for a B&W product a Kodak emulsion formula. This comes from a very authoritative source.

    PE

  5. #35

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    Quote Originally Posted by Photo Engineer View Post
    In no way is any Land formula for a B&W product a Kodak emulsion formula. This comes from a very authoritative source.

    PE
    ???
    Not what I heard.

    PE wrote:
    Kodak developed a series of products for him including some B&W and color products.
    I do not know which ones.

    Maybe it is a question of semantics.
    Are you saying you now think Kodak never produced emulsions for Polaroid?

    I recall reading that Kodak did under contract.

    I could be wrong, but probably not my source.

    I am not really interested in the process, other methods being superior in my opinion,
    but I will check to see if my memory fails me.
    Last edited by Ray Rogers; 08-28-2008 at 05:13 PM. Click to view previous post history. Reason: Read earlier posts...added quote found there.

  6. #36
    Photo Engineer's Avatar
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    I have this from authoritative sources that Kodak did not develop any emulsions for Dr. Land. We did R&D for Polaroid, but in all cases either the emulsions were from Polaroid, or we did R&D with our emulsions and using their proposed variations on format and formula and gave them the generic "answers" without Kodak knowing or producing the emulsion formulas.

    In no case did Land use a Kodak formula nor did he have one according to excellent sources.

    PE

  7. #37
    Mustafa Umut Sarac's Avatar
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    Ron , Do Kodak analyze the PN 55 film , if you want ?
    You can save everyone from guessing .
    If it would be for reasonable fee , I can order a report from someone who can do it and Ron referenced !
    May be Ron collect the donations and our group members would make a mark.

  8. #38
    Photo Engineer's Avatar
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    The emulsion is similar to Panatomic X, and that is all I know. This only comes from a Kodak analysis of a Polaroid product, and the fact is that it is the way it is, is because Land used standard Panatomic X for his first demonstration.

    For analysis, you need Scanning Electron Micrographs of the emulsion, along with X ray Diffraction and EDS data analysis for elements present. Even so, such work would miss Iridium, Osmium, Rhodium and probably Mercury, Cadmium?, and Sulfur + Gold levels. It would also miss any organic stabilzers and sensitizing dyes unless extremely precise Vapor Phase Chromatography or suchlike were done. An analysis could take several thousand dollars and weeks of my time analyzing the data.

    Even with that, you would then have to search Polaroid patents to pick package items from the patents such as the colloid type, and the coating amounts of the chemistry. After that, who will make the pods? Who will make the assembled package? Well, actually, who will make the emulsion and coating?

    You could use conventional film as Land did and formulate a single use goo. Then you could process in the dark using a paper you coated with a Carey Lea silver colloid.

    PE

  9. #39

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    Quote Originally Posted by Ray Rogers View Post
    ???
    I will check to see if my memory fails me.
    It seems I was correct.

    Jour. Opt. Soc. Amer., 37, Feb. 1947

    page 61

    Land appears to have written:

    "The writer also wishes to thank the Eastman Kodak Company for its cooperation in supplying a variety of special emulsions for this investigation."

    The help Kodak provided was significant and was not limited to a single process nor only to experimental material.

    From Type 40 and Type 47 on to the Polacolor negative, Kodak was involved.

    The relationship was not always peaceful, but Land and Damschroder (director of the Emulsion Research Division at Kodak) and Yutzy (another Kodak emulsion researcher) were on a first name basis and did a certain amount of after-work socializing.

  10. #40
    Photo Engineer's Avatar
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    Yes Ray, Land does state that. It does not say that they gave him the formulas. He tried PanX and said "can you do this to it" and they did, but did not sell or give him the formula. In other cases, he gave them emulsions and asked them to treat them with different chemicals and they did and supplied him with the emulsion or the coating.

    They did NOT, according to Kodak records, give Land a formula to make. I knew Rudy Damschroder quite well, as I worked directly for him for 1 year. He wouldn't even give some Kodak people formulas! He had established the "silver curtain" from which formulas did not issue! It was not until about 1980 that Kodak began to relax this internally and not until about 1990 that Kodak began to share some formulas with China. This latter, ceased recently.

    PE



 

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