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  1. #1

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    What chemical for anti reflection coating that dissolves completely?

    I have always wondered what is used on film backing as it liquefies completely in contact with water, leaves no stain or residue, yet must do a good job of preventing light piping and reflections. Can someone enlighten me?

    Russ

  2. #2

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    Do you mean the anti-halation coating?
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  3. #3
    AgX
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    Well, the antihalation coating is an anti-reflection coating, with halation being caused by reflection.
    Though it can serve other purposes too.

    Several different systems are employed. Furthermore aside of a coating of the backside of the film base a coating inbetween the film base and the emulsion is employed

  4. #4

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    Light piping is caused by light entering the edges of the film base. This is a problem with 35mm file but not other formats. To prevent this a dye is encorporated into the film base. This dye does not wash out as it is part of the plastic base. The amount of light piping is a function of the type of plastic. Estar (Kodak tradename for polyester) based film is more prone to light piping than is acetate based film.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  5. #5

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    Thanks for replies so far.

  6. #6

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    Dyes are generally used, but Kodachrome and movie films use(d) a carbon coating called rem-jet on the back . http://photonotes.org/cgi-bin/photo-...ihalationlayer
    testing...



 

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