Removing Anti-Halation Backing from sheet film

Discussion in 'B&W: Film, Paper, Chemistry' started by htmlguru4242, Sep 26, 2005.

  1. htmlguru4242

    htmlguru4242 Member

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    I've been trying to find some sheet films without an anti-halo layer, for some work I'm doing (check on the "Autochromes" forum under "Alternative proceses". I've determined that the only film that fits these characteristics (IR820c "Aura") is far too expensive for experimental purposes.

    I know that some anti-halo layers are water-soluable, but soaking film in water to remove it will remove the panchromatic sensitizing dyes in the emulsion.

    So I was thinking, because only the backing of the film must be soaked in order to remove the anti - halo dyes, why not find a way to protect the front of the film from becoming wet. So I came up with an idea: Why not place the sheet film, emulsion-side-down, on a plastic or glass sheet that is slightly larger than the film, and tape the sides of the film to the plastic. This way, the emulsion is sealed against plasic, completely shielded from water. This way, you could soak the sheet (or even use some type of bleach) to remove the anti-halation layer. (This would, obviously, be conducted under complete darkness). The film would then be dried and un-taped. Does anyone think that this would work?

    I'm getting some J&C 4x5 sheet film this weekend, and want some feedback before trying it.

    Basically, it would look like this:
    [​IMG]
     
  2. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    Sounds messy, but what would it hurt to try a few sheets?

    Why not also try soaking, just to see what you get? Maybe the result would be some slow orthochromatic film, but it's all about the look, so maybe it might look interesting.
     
  3. Donald Qualls

    Donald Qualls Member

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    David, ortho film wouldn't work for Autochromes -- it's a primitive color reversal material, using a single layer filter with very small filters (grains of dyed starch, originally), and if the film won't record red, you'll get dark (because all the red grains have black behind them) cyan (because the rest will be green and blue) transparencies.

    And the filtration costs a lot of light, so slow film is a hard thing to deal with, too. I'd consider ISO 100 about the minimum useful speed for the parent film, and faster would be a lot better.
     
  4. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    I must have skimmed past that bit about autochromes. I though he was just after the halation effect. Oh, well.
     
  5. glbeas

    glbeas Member

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    Definitely try it, but watch very closely to make sure the film base stays dimensionally stable. I think acetate will change size with the moisture content won't it? If it does you may see the film bow out where its been wet. Hopefully it will flatten again as it drys.
    If an Estar base film makes itself available that may be a better way to go.
     
  6. glbeas

    glbeas Member

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    A thought too, some printers can handle a fairly thick sheet fed through a slot in back. Might be good like that feeding the film taped to the plastic to put the filter matrix on it. My Epson 2200 is built like that.