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  1. #31
    Photo Engineer's Avatar
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    I'm sure we are misunderstanding each other. The patents surely don't teach everything, nor do the texts. Having disassembleld the Polaroid products, and built them from scratch (in color) I understand the difficulties with this.

    The silver image must be stabilzed against oxidation and sulfurization. A pyrazole compound among others lends its odor to the lacquer used. It also helps adjust pH.

    In addition, the coating has timing layers and neutralization layers to prevent over development. The breakdown of the timing layer changes with respect to temperature, thereby mitigating any temperature effects. Otherwise, on a hot day the Polaroid print would overdevelop. Even so, they give times of development (lamination) for different ambient temps.

    Kodak's Ektafllex peel apart print material had to have the same thing built into both the donor and reciever materials in order to get the right image quality and stability. So, it is needed for both B&W silver and color.

    For more information, I refer you to patents by Barr, Bush and Thomas assigned to Kodak. Jack Thomas later became VP and Director of Research for Kodak. You may also want to look at patents by Henzel, and also by Armour and Mowrey.

    PE

  2. #32

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    marhaba mustafa-asalamu alekum

    the original research land did for his first patents was done here in nyc at the main public library on 42nd and 5th-they have some interesting materials

    photo engineer-any ideas why my 4x5s where leaving an inch of so of the image on the last edge in the pod today?-temp in the high 80s the culprit i suspect

    will hollar at sue gagnon at polaroid when she gets in but since you might know i might ask-and get an answer

    vaya con dios

  3. #33
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    High temp, high pH and soft gelatin = iffy situation.

    I've seen high pH solutions reverse the hardening of gelatin completely by simple hydrolysis. Then you end up a complete mess. If it is at the pod end, that is where the pH is highest.

    PE

  4. #34

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    Quote Originally Posted by Photo Engineer View Post
    High temp, high pH and soft gelatin = iffy situation.

    I've seen high pH solutions reverse the hardening of gelatin completely by simple hydrolysis. Then you end up a complete mess. If it is at the pod end, that is where the pH is highest.

    PE
    muchismas gracias p e

    no time to speak with ms gagnon today so your reply was right on time

    you got any thing to say about the pos/neg-not 55-i think 51?

    its iso 600+ for the print which is for grafic arts use but the neg is supposed to be medium contrast(?!?!?!?)

    non in stock where i usually look so i still can't test

    vaya con dios

  5. #35
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    I know nothing about the other products. Just generalities about the chemistry, and even that is fading.

    Sorry.

    PE

  6. #36
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    I read your message photo engineer which saying you are sorry to not see the applicants of your posts.
    Let me try instant photography. My english is weak and when it comes to 60 years old technical patent english , it is weaker.
    I have a polaroid 350 and money to buy hungrian bw photopapers.
    I am a practical person .
    Now what do I need to do for to get positive , instantly developed and fixed results from the photo paper which is exposed in polaroid 350 .
    Let AgX and you write whatever we need , step by step and with explaining how we measure ph and others. What will be the temperatures of chemical mixing stages , how can we do with cheapest , non toxic and easiest to find materials not polaroid patent chemicals.
    I did not start to this polaroid business because I could not understand whatever told.
    If you are willing to teach to a idiot , you can grasp the fruits from the tree.
    I am willing to invest this method and mixing and selling the chemicals.
    If I succeed than I will go to kodachrome and try.
    If I can do it , everyone can do it.

    Best ,

    Mustafa Umut Sarac

  7. #37
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    Mustafa;

    Polaroid B&W materials depend on development in an environment high in silver halide solvent, so that the positive image is formed from the salts dissolved as leftover from the negative image. These are depositied on nuclei in the reciever sheet from the donor sheet (the original exposed negative).

    Imbalance results in loss of speed and tone scale.

    So, with balance, you get both a positive and a negative. The positive is what we generally want, but sometimes we want both. Polaroid has offered products that do both.

    In any event, the dissolved silver halide (positive) migrates to the reciever sheet and precipitates out to form a positive image by reduction and we have both a negative and a print.

    This is B&W silver only.

    In color, the color dyes are hydroquinone containing azo dyes. They dye that developes silver becomes a quinone and is insoluable. The remainder (positive) is soluable and migrates to a mordant sheet. This forms a positive image.

    Neither method was in the capability of Land, so Kodak made the original materials, but they were made under strict secrecy according to agreements between companies.

    The result is that I know little about the materials due to that secrecy. Kodak would not let employess know what was done between companies.

    PE

  8. #38
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    It took 6 years.
    Maybe somebody can boast a recipe homemade instant photo?
    We have time. But it does not give us more time.

  9. #39
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    Quote Originally Posted by Redf View Post
    It took 6 years.
    Maybe somebody can boast a recipe homemade instant photo?
    Hi Redf,

    I think fastest way to home made instant photos would be to follow http://new55project.blogspot.de and try to make similar solution in format you want.

    regards,

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