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  1. #11
    gainer's Avatar
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    We need to devise a special diet for photographers that will promote the production of nose oil.

    I think it was the people who made Omega enlargers who had an oil immersion negative transport for 35 mm photographers who have the most problems with these fine scratches. I wonder if they sold nose oil to go with it.
    Gadget Gainer

  2. #12

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    Dear Smudger,

    Consider trying scanning fluid. Watch the flammability though when comparing brands.

    Neal Wydra

  3. #13

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    Quote Originally Posted by Neal View Post
    Dear Smudger,

    Consider trying scanning fluid. Watch the flammability though when comparing brands.

    Neal Wydra
    Or turn-signal fluid?

  4. #14

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    Quote Originally Posted by PHOTOTONE View Post
    Hard to use nose oil if you are printing 100 negatives in a session.
    Do you know of someone with this many scratched negs?

  5. #15
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    The alternative oil to use is a type of silicone oil which does not evaporate and form a skin like turpentine. This is used in all wet gate printing.

    PE

  6. #16
    gainer's Avatar
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    Quote Originally Posted by jim appleyard View Post
    Do you know of someone with this many scratched negs?
    It could happen if its due to a scratch on the film path and you run 3 or more 36ers through before you find it. Reminds me for some reason of the "Dont you just hate it when..." skits I used to see on Saturday Night Live.
    Gadget Gainer

  7. #17
    Dave Krueger's Avatar
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    Luckily I have some reagent grade nose oil...

  8. #18
    AgX
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    One should distinguish between scratches

    -) on the emulsion side
    -) on the base side

    (In case the base has a dulling layer refer to the first case. Antistatic surfaces on the base should be of no interest I assume.)

    The refractory index of gelatin is said to be 1.51 (with listings going from 1.465 to 1.550)
    A coating of some thickness (with the same ref.index as gelatin) on the emulsion side could reduce contrast but could also make image details visible again.

    (Tri-) Acetate has a refractory index of 1.48

    Polyester of 1.64


    a) Coatings in order to fill the scratches:

    Glycerine has a refractory index dependend on the amount of water absorbed covering the range given above.

    Tetrachlorethylene: 1.50 (very volatile though)

    A mixture of 9 parts Toluol an 1 part 1,1,2 Trichloro-1,2,2-Trifluoro-Ethane: 1.50

    Oil of cloves*l: 1.55

    Chinoline: 1.628

    Monochlornaphtaline: 1.633

    Monobromenaphtaline*: 1.656

    *could be mixed too

    (the tolerance between emulsion or base and the coating should be within 0.02 .


    b) Coatings just to give a dulle surface in order to countereact the refractory effect,

    c) dulling by another means,

    d) Smoothening the gelatin, and thus the scratches, by repeated swelling and drying


    I got all these ideas from a publication of our fellow member Gigabitfilm, who once made a factor-1000 enlargement of a pictorial negative and thus looked into film-surface problems.
    Last edited by AgX; 12-22-2007 at 05:25 PM. Click to view previous post history. Reason: tolerance

  9. #19
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    Quinoline (Chinoline in German), Monochloronapthaline and Monobromonapthalene are all quite nasty. I would avoid them at all costs. The other mixtures or chemicals such as tetrachloro ehtylene and the Toluol are not much better and the Toluol is quite flammable. The latter two are volatile.

    No, you need a non-volatile liquid that does not absorb moisture. Nose oil, glycerine and silicone oils will fill those requirements and are also relative to the ones mentioned above, non-toxic.

    PE

  10. #20
    AgX
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    To be fair to Gigabitfilm, he also referred to a silicone oil “Refrectasil” from the USA from 50 years ago with an refractive index of 1.46. But as I do not know whether this is still about, and for the rest silicone oils are not standardized I did not refer to silicone oils.

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