Image size on dried fibre paper

Discussion in 'B&W: Film, Paper, Chemistry' started by Sim2, Aug 26, 2012.

  1. Sim2

    Sim2 Member

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    Hi there, this may well be an odd question - but here goes...

    Had anyone else noticed a difference in the paper size once a fibre base print it dried?

    Ok, so I print on 8"x8" paper with an image size of 7"x7". The paper is cut accurately on a trimmer and the image size is consistent on the easel. I dry the paper by taping it to a glass sheet with artists brown tape. When the print is dried, one dimension of the image size has gone up to 7 1/8" and the other dimension has reduced by 1/16". This is consistent over about 20 prints that have been printed/dried over the last few weeks using a variety of Ilford papers.

    Has anyone measured the finished image size of their prints? If so, have they remained the same as the initial exposure print size. Not sure what to do with this info but it does seem consistent on my workflow!

    Thoughts welcomed. :munch:
     
  2. Maris

    Maris Member

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    Fibre base paper changes size when taken through a wet/dry cycle. The direction and magnitude of the change depends on the individual paper and the machine direction of the paper fibres. If accurate registration of multiple images is required then RC paper is consistently reliable.

    Soaking and drying FB paper prior to exposure and processing reduces the size change problem but is such a nuisance I only tried it once before going to RC.
     
  3. Photo Engineer

    Photo Engineer Subscriber

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    Yes, this size change is normal for FB paper and Acetate film base. This is one of the seldom mentioned benefits of RC and Estar type bases.

    PE
     
  4. Michael R 1974

    Michael R 1974 Subscriber

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    I knew about fb paper, but not film. Are any current B&W films even coated on Estar? I'm surprised about the film changing size. If this is true, how is it that masking works? Wouldn't the mask be out of register once processed?
     
  5. Sim2

    Sim2 Member

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    *Just musing to myself here really*
    I have been aware that the fibre paper swells when wet (and potentially shrinks when drying), I guess that up to actually measuring the print image size I hadn't followed the logical thought process that with the "grain" of the paper fibres going in one direction the actual swelling/shrinkage may not be totally consistent across a sheet. What I think I mean is that if the centre of a print is the reference point the top/bottom and left/right sides may not expand equally by the same amount.

    The follow-on thought is that the image on the paper has been stretched/distorted (very slightly) in one measurement e.g. width in relation to the height. Ho hum - good job I don't have to produce a dimensionally "accurate" image of the subject!
     
  6. tkamiya

    tkamiya Member

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    I noticed Ilford MGIV shrinks quite a bit.
    I also noticed Adorama house brand paper doesn't change its size.
    I have a book somewhere here that talks about a peper that actually expands when dry....

    The rate of change seems to be pretty consistent, so I just account for it when size is important. I always let it dry overnight then hot press, then cut my mat because of this.
     
  7. Photo Engineer

    Photo Engineer Subscriber

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    All masking and matrix film was made on Estar. It was done to prevent registration problems.

    All paper materials shrink or expand depending on length vs width (warp vs woof! :D ).

    PE
     
  8. Michael R 1974

    Michael R 1974 Subscriber

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    Right, but most people currently use either regular fine grained films or ortho or ortho litho-type for things like unsharp masking, not specialized masking film (does Kodak even make that stuff anymore?). So I wonder why nobody is having problems... ?
     
  9. Photo Engineer

    Photo Engineer Subscriber

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    Some films are on acetate and some are on Estar and it is up to the user to check the support.

    PE
     
  10. NB23

    NB23 Member

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    You've done that? Wow, you were very brave!
     
  11. Maris

    Maris Member

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    Yes, I was trying to make a long "panorama" by sticking photographs edge to edge with the details lining up in accurate register. Using fibre base paper is not an easy way to go about this!
     
  12. HelenOster

    HelenOster Member

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    Good to read! Thanks
     
  13. Neal

    Neal Subscriber

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    Dear sim2m,

    A small addition. If you like exceptionally glossy prints, using a ferrotyping print dryer almost eliminates the shrinkage.

    Neal Wydra
     
  14. Michael R 1974

    Michael R 1974 Subscriber

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    Great :sad: another rat hole for me to venture down. Troubling that in everything I've read by the masking gurus (Burkett, Bond, Radeka etc) I don't recall ever seeing any mention of this variable in chosing the masking film. They all use and recommend a variety of films from TMax to FP4 to Ortho Plus to various slow ortho/litho films.
     
  15. Michael W

    Michael W Member

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    I discovered this paper size change late last year when I was making test prints on a few papers from different manufacturers. I'd done the best I could on one paper and was then seeing what I could get out of the neg on another. I was squeegeing the prints on a perspex board and lining them up next to each other. I soon found that one of the earlier tests which had air dried for an hour or so was considerably shorter than the newer, still damp print. Quite a surprise. I'd forgotten about it until now, so it's good to get an explanation.
     
  16. Photo Engineer

    Photo Engineer Subscriber

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    See my post #9. Many sheet films are coated on Estar to enable masking and other critical processes.

    PE
     
  17. Michael R 1974

    Michael R 1974 Subscriber

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    How about polyester? (eg Ilford Ortho)
     
  18. MartinP

    MartinP Member

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    Estar is a Kodak trademark for a polyester plastic.
     
  19. Michael R 1974

    Michael R 1974 Subscriber

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    thanks.
     
  20. papermaker

    papermaker Member

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    This is basically correct. The swell and shrink depend on the fiber orientation and on the stress/strain during drying. On the paper machine, the sheet stretches in the machine direction and shrinks in the cross direction. On re-wetting, the sheet expands more in the cross direction than in the machine direction. The MD/CD fiber orientation of the sheet can varying across its width (as can the stress/strain) so that its wet expansion will also vary. While these generalities apply to most fiber base papers, specifics depend on the actual paper in question.