How to flatten FB prints

Discussion in 'Enlarging' started by Bruce Robbins, Aug 11, 2013.

  1. Bruce Robbins

    Bruce Robbins Member

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  2. Ken Nadvornick

    Ken Nadvornick Member

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    One should be careful, however.

    I have done similarly by very lightly misting the backs of dried curled prints before giving them a quick shot in a heated press. The idea was to simulate the "steaming" effect of ironing shirts in order to remove the curling.

    It worked beautifully. But it also had a tendency to affect the surface texture of the print. It flattened the normal textured surface of air-dried unferrotyped glossy prints. This tended to reduce the "sparkle" and give a veiled look I found quite unpleasant.

    While the method described in the link doesn't use heat or clamping, it does use pressure against the surface texture of a lightly dampened print. So when using this method it might be wise to keep an eye out for those texture changes.

    I should also note that I regularly fix prints in homebrew Kodak F-24 fixer, which is non-hardening. This helps with subsequent toning, but may also increase the chances for surface texture alteration.

    Ken
     
  3. Gerald C Koch

    Gerald C Koch Member

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    FB prints can be prevented from curling by soaking them in a dilute solution of glycerin or similar humectant before drying. Try 2 ounces of glycerin and 30 ounces of water. Depending on your average local humidity the amount of glycerin can be altered.
     
  4. semi-ambivalent

    semi-ambivalent Subscriber

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    A question: The altering, would it be more glycerin for areas of less humidity or less glycerin? Will try this as soon as I can find glycerin, maybe the drugstore.

    s-a
     
  5. Bill Burk

    Bill Burk Subscriber

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  6. Gerald C Koch

    Gerald C Koch Member

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    You can use more glycerin if you are in an area of low relative humidity. Using too much will result in prints that feel a bit damp. At one time there were several commercial products such as Pakasol and Edwal Print Flattener.
     
  7. nworth

    nworth Subscriber

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    Gerald's solution used to be sold as Ansco Print Flattening Solution. It works decently in most places, at least for a while. Mounting on heavy matboard seems to be the closest thing to a definitive answer. There is a long, persistent discussion of this problem in the B&W Film, paper, etc forum here on APUG.
     
  8. blockend

    blockend Member

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    I used to dry FB prints with a hairdryer. It's a labour intensive method but gets prints flat enough to finish off under a pile of books. Squeegy away excess water and point hair dryer at one side of print from about one foot away. As soon as it curls towards the hair dryer, point at reverse side. Continue the process. Towards the end the print will hardly curl at all when heat is applied. Typically, the print will be flat or show a very slight upward or downward curve that can be cured by weight.

    Cheap, but time consuming.
     
  9. Jim Jones

    Jim Jones Subscriber

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    When producing 8x10 prints in a basic darkroom, placing up to 32 of them in a twin bed and covering them with a sheet and blanket helped them dry fairly flat. Storing them alternately face up and face down in tightly packed photo paper boxes eventually completely flattens them. They may curl when removed from these boxes, depending on humidity.
     
  10. mr rusty

    mr rusty Subscriber

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    In my short darkroom career so far, I have found taping to a piece of glass (actually the toughened glass front panel of an old TV) using gummed tape works perfectly. If I was doing hundreds of prints it would be a hassle, but it's part of my routine to limit to 2 FB prints at a time (which is the size of my glass). They really get under tension as they dry and "ping" noticeably when I run the blade around the edge to cut them off. The residual tape soaks off the glass easily. Works for me. YMMV.