What chemical for anti reflection coating that dissolves completely?

Discussion in 'Silver Gelatin Based Emulsion Making & Coating' started by rwhb12, Mar 16, 2013.

  1. rwhb12

    rwhb12 Member

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    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. Gerald C Koch

    Gerald C Koch Member

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    Do you mean the anti-halation coating?
     
  3. AgX

    AgX Member

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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. Gerald C Koch

    Gerald C Koch Member

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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.
     
  5. rwhb12

    rwhb12 Member

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    Thanks for replies so far.
     
  6. kevs

    kevs Member

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