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Thread: Red window problem again

  1. #1

    Red window problem again

    As usual, when I make or modify a camera, I first cut a piece of paper for the first test shot before spoiling a roll of film. This time it concerned an AGFA ISOLA (something like the Balda Baldixette, no folder with bellow but a tube coming out)
    Well, I went to the darkroom, cut a piece of Multigrade, loaded the camera and went outside. Exposure 7,5 minutes. The camera was exposed to inside light and daylight not longer then 12 minutes. Here is the result (reveresed and mirrored)
    I never had that before, So I made a second exposure with the film counter window taped black and all was o.k..
    On previous tests during the summer with other cameras the times between loading cameras and going back into the darkroom were shorter and I didn't have the problem.
    Does somebody outside ther know if the little red window of the Isola is more sensible then other ones or if 12 minutes in red light just is to long for Multigrade IV ?
    First photo: film counter open, second one: taped Attached files

  2. #2

    Red window problem again

    Taco, I think this is a typical Isola effect , I have modified three of them with different focal-lengths ( 65, 40
    and 28 mm). Each of them needs black tape for the red window ( different paper ) , but it`s a good body for modifying.

    Bino

  3. #3

    Red window problem again

    I believe it will happen only with paper, once the roll has the blocking paper attached to the film. Perhaps the old red coat lost part of its color.

  4. #4

    Red window problem again

    Fixing this is just another use for litho tape, available at printing or art supply stores. It is a high quality tape intended to block all but red light. Once you have some of it, you may find it good for countless uses.

  5. #5

    Red window problem again

    Quote Originally Posted by bino
    Taco, I think this is a typical Isola effect , I have modified three of them with different focal-lengths ( 65, 40
    and 28 mm). Each of them needs black tape for the red window ( different paper ) , but it`s a good body for modifying.

    Bino
    How did you manage to do that? With my model, with the tube not completely out, the shutter just doesn't work. Even if I could fix that, with the tube in I would get vignetting: a nice round negative.
    That was my first idea: making a zoom pinhole. o.k. The hole would be either to large with the tube in or to small with the tube out or I could have tried to work with two pinholes somehow held in place with a magnet but I could not resolve the two problems mentioned.
    Are we talking about the same model of Isola? Mine looks like attached.
    Attached files

  6. #6

    Red window problem again

    Two Isolas, one Dacora Digna ( I make the same with a third Isola, but gave it away to a friend , cheaper than Zero 2000 )

    Attached files

  7. #7

    Red window problem again

    Quote Originally Posted by bino
    Two Isolas, one Dacora Digna ( I make the same with a third Isola, but gave it away to a friend , cheaper than Zero 2000 )
    And how did you fix the shutter problem?

  8. #8

    Red window problem again

    Taco, I had this problem with one of my 4" wide paper rollfilm cameras. I was using a deep red filter as a viewing window, and had masking tape squares, with frame numbers, in the center of the reverse side of each paper negative, that would line up with the window when the paper roll was advanced properly.

    I made the mistake of not testing prior to taking the camera up to Santa Fe. Had some real nice exposures - except for the big, white dot in the middle.

    Even though paper is not supposed to be red sensitive, these red filters still pass enough light of shorter wavelengths to fog paper directly. I then thought about how these old medium format cameras actually worked: they had an opaque paper backing strip. So my subsequent paper rollfilm cameras use the paper negative strip rolled up with a strip of black opaque paper; the frame numbers are taped to the reverse side of the black paper.

    Jim, I have never tried litho tape for this application; if it prevents fogging of photo paper in direct sun, that would be great.

  9. #9

    Red window problem again

    Quote Originally Posted by Joe_VanCleave
    Jim, I have never tried litho tape for this application; if it prevents fogging of photo paper in direct sun, that would be great.
    Litho tape might not be an improvement over a deep red filter. It is intended for use with blue sensitive or orthochromatic material. However, many layers can be used.

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