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Thread: Unexplicable exposure problem with paper negatives

  1. #1

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    Unexplicable exposure problem with paper negatives

    Over the last few months I've been getting unexplained results for paper negatives [pure white after development] except for very long [2 minutes or greater] exposures
    My two Weston V meters checked against Nikon digital camera [100ISO digital camera setting versus 6ISO paper negative]. Gave same ‘reflected’ result after correction for change in ISO rating.

    Used four 4x5 paper negatives cut from single 8x10 multigrade paper. Prior paper from same box gave four obviously exposed images
    Last tests done with incident readings with sun diagonally behind subject. Camera 3m in front of subject. Same subject and camera-subject distance for all four exposures. All images taken in about 30 minutes.

    Four images using 4 different lenses
    135mm xenar in copal #0 shutter
    4 ¼ inch Wray no shutter, but hat used to control length of exposure
    180/315mm Symmar convertible with Ilex shutter – used in both configurations

    Both shutters checked for operation and speed accuracy by 'Romanian' tester, and also checked that shutter worked by eye.
    Copal as per setting on ‘speed ring’.
    Ilex - Actual speeds determined at speed selector dial position.
    Way out of speeds on dial, but reasonably consistent

    Weston Reading 12 - 12.5 giving exposures of:- 1/8s@f11; 2s@f25; 1/10S@f8 and 1/2s@f22.

    The four exposed sheets developed at same time in Jobo 2500 tank with 2504 sheet film holder.
    Developed with ‘’Ilford PQ universal” using both old [2 ½ years old} and fresh concentrate [delivered yesterday opened today]
    Dark slide removed before exposure.
    Camera:- Calumet CC400

    Any and all help welcome

    regards
    Tony

  2. #2

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    Re: Unexplicable exposure problem with paper negatives

    What paper did you use ?

  3. #3

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    Re: Unexplicable exposure problem with paper negatives

    Did you load all the sheets emulsion side out? A sheet loaded backwards will not be exposed. Not to be insulting... we've all done something similar.

  4. #4

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    Re: Unexplicable exposure problem with paper negatives

    What kind of light?

  5. #5

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    Re: Unexplicable exposure problem with paper negatives

    Quote Originally Posted by koraks View Post
    What kind of light?
    “Last tests done with incident readings with sun diagonally behind subject. Camera 3m in front of subject. Same subject and camera-subject distance for all four exposures. All images taken in about 30 minutes.”

  6. #6

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    Re: Unexplicable exposure problem with paper negatives

    Quote Originally Posted by Mark Sampson View Post
    Did you load all the sheets emulsion side out? A sheet loaded backwards will not be exposed. Not to be insulting... we've all done something similar.
    no insult taken - have done so on occasion but not this time

    Quote Originally Posted by Pere Casals View Post
    What paper did you use ?
    multigrade MGIV RC de luxe Pearl

    QUOTE=koraks;1503106]What kind of light?[/QUOTE]
    Quote Originally Posted by Bob Salomon View Post
    “Last tests done with incident readings with sun diagonally behind subject. Camera 3m in front of subject. Same subject and camera-subject distance for all four exposures. All images taken in about 30 minutes.”
    Daylight early afternoon bright for UK

    regards
    Tony
    ps the paper has an unknown history. I'm another unknown history box [5x7] which I might try out to see if I've some 'bad paper' in the midst of the 8x10 box

  7. #7

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    Re: Unexplicable exposure problem with paper negatives

    I'd say exposure is a tad on the short side (at least to my taste) but not to the extent that no image would be visible. I'd advise on doing some further testing with tray development so that you can see what you're doing. That way you can at least check of something comes up if you extend development. But it's a mister for sure! Does the paper print OK under normal (enlarger/contact) conditions?

  8. #8
    Andy Eads
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    Re: Unexplicable exposure problem with paper negatives

    Dead or contaminated developer?

  9. #9

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    Re: Unexplicable exposure problem with paper negatives

    Quote Originally Posted by koraks View Post
    ! Does the paper print OK under normal (enlarger/contact) conditions?
    Don't know, but paper from the 100 box 'worked' without [processing] problems up until [say] 6 sheets ago.


    Quote Originally Posted by Andy Eads View Post
    Dead or contaminated developer?
    I tested today with an unopened developer concentrate [delivered yesterday from supplier]. All containers washed between times.

    regards

    Tony

  10. #10
    Jac@stafford.net's Avatar
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    Re: Unexplicable exposure problem with paper negatives

    No disrespect intended. As I told my students, and as I was taught, first remove all questionable variables. That means one batch lot of non-expired media (paper in this case), certifiably fresh chemistry, one light meter, one lens in same shutter, same time/temp processing.

    Experiment with the above until you find your desired outcome. Record the details (above), and then REPEAT the whole regime exactly and if you do not get acceptable results, something in the chain of requisites wrong. Operator error, whacked shutter speed, aperture is where I would look first.

    Best of luck and please stay in touch. I am sure a lot of us are looking forward to your success.

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