Foma paper darkens as it dries problem

Discussion in 'Enlarging' started by pbails, Jul 4, 2010.

  1. pbails

    pbails Member

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    Hi
    I am a beginner with b & w printing and have the following problem, (if it is in fact a problem). I am using FOMA paper (Fomaspeed Variant RC glossy). I am trying to ascertain the exact exposure time to achieve a solid black in the paper. I am doing this by doing contact prints of clear film at different times. I notice that as the paper dries the faint greys on the paper seem to become more black to the point where they disappear and the whole paper simply looks solid black. E.g. if I do a contact print of clear film for 13 seconds at f11 I can see (faintly) the outline of the film while the paper is wet but once it dries the whole sheet looks uniformly black, (to my novice eye).

    Any advice about this would be much appreciated.

    peter
     
  2. Ian Grant

    Ian Grant Subscriber

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    Hi Peter, welcome to APUG.

    This is called dry down, you need to allow for i when printing, it's not normally that much with RC papers. Your aiming for that point where it dries to the maximum black so that sounds OK.

    Ian
     
  3. Adrian Twiss

    Adrian Twiss Member

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    You say you are using clear bits of film. Are you developing the film rather than just fixing it to clear it? You need to develop it as well to take account of the slight chemical fog that occurs with all development processes.
     
  4. jp498

    jp498 Member

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    Fomapan 311 does have a little of this, maybe less than 5% like others have posted. Something is wrong with your process if things go from light grey to black though.

    I would not waste paper of clear negatives to find the black point. Do a test strip print of the negative you want printed. If you had a 20 second exposure, you could move a piece of cardboard in 4 4 second steps to have 5 exposures represented on the paper. Then pick one or extrapolate between two to have the exact exposure that looks right to you.
     
  5. ic-racer

    ic-racer Member

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    Microwave oven, hair dryer or an old print dryer can speed up the process.
     
  6. Wade D

    Wade D Member

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    When I do test prints I use an exposure where the subtle whites are not evident when the print is wet. Using a microwave to dry the test print I can see if the whites dry down to a pleasing value. The same test can be done to determine maximum black with minimum exposure.
     
  7. OMU

    OMU Member

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    Also be aware that Foma is very sensitive to yellow safelight.
    I started to try out Foma tree months ago and had to change my safelight from yellow to red.
     
  8. pbails

    pbails Member

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    Thanks everyone for your help. I am using some film that was developed clear and a red safelight and I don't really mind wasting some paper at this stage of my slow learning curve. I'll try the microwave / hairdryer drying technique to speed things up!
    peter
     
  9. Rick A

    Rick A Subscriber

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    When you state the paper goes from feint gray to black, it has me concerned about how long you are fixing the paper. In my experience with Foma, it only dries down about 5%(find desired exposure then subtract from print time for dry down)which would put light gray to barely darker light gray(maybe 1/4 stop max depending on time). Insufficient fixing could cause your print to darken to nearly black. My question to you is how long do you fix your paper, and are you turning on a white light too soon.
     
  10. sly

    sly Subscriber

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    Rick, I read his post differently - I don't think a faint light gray is drying to black, but that a very dark gray, just discernable when wet is drying to black. Dry down would cetainly account for that.

    pbails- try googling Les Mclean - he has a great article on dry down. I'd put the link in here, but I'm not comptuer savvy enough. (His split grade printing info is really useful too.)
     
  11. MattKing

    MattKing Subscriber

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  12. clayne

    clayne Member

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    I wouldn't try it with RC paper. The microwave trick generally refers to testing for dry-down with FB papers.

    However, if the entire print goes uniformly black you have other problems. I'll assume you really mean dry-down as paper printing out doesn't usually go black. If so, then yes you need to provide some amount of under-exposure to account for dry-down as others have pointed out.
     
  13. fschifano

    fschifano Member

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    I use a lot of that paper as sold by Freestyle under the Arista.EDU Ultra label. Compared to some other RC papers, this one exhibits a little more dry down effect than some others I've used, but I also think you have other things going on here that are not right. The dry down effect is somewhere between 5% and 10%, but I've calibrated everything to a dry print - not a wet one so I don't have an exact figure.

    BTW, a hairdryer is the most convenient way to dry down a test RC print. The microwave works better for fiber based papers.
     
    Last edited by a moderator: Jul 7, 2010