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  1. #21
    Photo Engineer's Avatar
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    Chris;

    You have it right. The tolerance is 0.001" or 1 mil.

    Tjaded;

    I may end up in the funny farm!

    PE

  2. #22
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    I'm surprised that you can actually coat the final width directly with those, if I understood correctly.

    I've been under the impression that you must leave some edges to be trimmed out. My blade leaves a millimeter or two of uneven coating at edges, and I need one centimeter or so for both sides so that the blade runs reliably on the film base.

    Can you get usable coating edge-to-edge with those?

  3. #23
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    Hrst;

    Due to surface tension and other effects, the edges are always defective. This is called the selvedge. If you look closely at the support next to a film roll, you will see that the film is wider. The coater is also wider, but just right for the support. When you are done, you must trim the edges. I have to set up a trimmer for that.

    In practice, Kodak coated 42" wide paper to get 40" of good coating. The edges were used for traction during movement through the machine and for the selvedge. The actual coating station was just over 40" wide. My 8" blade is 8.25" giving 0.25" of selvedge.

    PE

  4. #24

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    Interesting, don't understand this yet but will keep reading and learning.

  5. #25
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    I see now that the roll of acetate is about 5mm wider than a 120 roll, so that gives you some selvedge. However the blades look even wider than the roll, but they don't look like 8", more like a bit under 3". Are they going to work with this roll of acetate?

  6. #26

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    Sounds cool. Maybe make a section on 120 film making for Vol.2 of your book.

    Kirk
    Kirk

    For up from the ashes, up from the ashes, grow the roses of success!

  7. #27
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    Quote Originally Posted by polyglot View Post
    I see now that the roll of acetate is about 5mm wider than a 120 roll, so that gives you some selvedge. However the blades look even wider than the roll, but they don't look like 8", more like a bit under 3". Are they going to work with this roll of acetate?
    Yes, it will work. I've already tested it in dry runs.

    PE

  8. #28

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    Sounds like including the selvedge in the image might produce an interesting effect. How about coating some actual 120 size acetate and not trimming the edges..?

    Regards
    Jerry

  9. #29
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    Jerry;

    That is an interesting idea, but the selvedge makes the coating a tad overwidth by my measure, so it will have to be trimmed. In any case, it might just leave a black line down each side. IDK. I may try. This is months in the future.

    Thanks.

    PE

  10. #30

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    Hello PE

    If you don't mind me asking, where did you get the acetate base? I am assuming that it isn't an off the shelf item.

    Just think-- homemade 120 film -- I will start saving my backing papers now
    rob

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