Kodak Polycontrast filters

Discussion in 'Kodak' started by iga, Apr 21, 2005.

  1. iga

    iga Guest

    Hi all !
    I got a Kodak Polycontrast filter kit ( model A )
    It's an older one, under the lens 7 filters kit.
    Anybody knows if exposure compensation is needed
    for different grades ? I was told that there was some
    kind of "exposure calculator" for this kit, but
    unfortunately I can't find it.
    iga, Apr 21, 2005
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  2. iga

    UC Guest

    Yes, there was. Write to Kodak, in case that thought didn't cross your
    UC, Apr 21, 2005
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  3. yes compensation is required. I don't use a calculator - I do test strips
    for each contrast grade change. Bit I looked in my Kodak B&W dataguide
    sixth edition, copyright 2001 and found on page 48 the following:

    "There is no change in effective paper speed within the range -1 to 3 1/2
    and within the range 4 to 5+. You need to recalculate exposure when you
    switch from one range to the other, or when you remove the filter completely
    or add a filter when you have been printing without one."

    The explnation then goes on to describe how to set the calculator (page 49).
    I'll give you an example to show the factors:

    If the "no filter" print time is 10 seconds, then the "-1 to 3 1/2" range is
    20 seconds and the "4 to 5+" range is about 41-42 seconds.

    Thus for going from no filter to a "-1 to 3 1/2" doubles the time.
    Going from no filter to a "4 to 5+" increases the time by a factor of
    slightly more than 4.

    Going from a "-1 to 3 1/2" to a "4 to 5+" will about double the time (20
    seconds to 42 seconds, for example)

    This calculation seems constant. The same multipliers apply to all paper
    speeds, chemicals, etc (or at least there is no compensation on the
    calculator dial for anything but filer grade changes).

    Hope this is helpful.
    Pieter Litchfield, Apr 21, 2005
  4. iga

    UC Guest

    This is for the NEW set. The old set was different, and each filter
    required a different factor.

    You need the calculator.
    UC, Apr 21, 2005
  5. iga

    iga Guest

    Yes, it's an older one. And yes, I'm afraid that I need
    the calculator. The problem is that I don't know where
    to get one..
    iga, Apr 21, 2005
  6. iga

    UC Guest

    Write to or call Kodak. They'll be glad to help you!
    UC, Apr 21, 2005
  7. Sorry - you are right - the title says "When you change from one Polymax
    filter to another:" I don't have anything relating to the older filter
    sets. I have one that is about 30 years old and has 5 filters, but I don't
    use it - it's on the "museum" shelf.
    Pieter Litchfield, Apr 21, 2005
  8. Looking at the calculator in an old databook, listed below are the
    adjustment factors, which you could use to set up your own calculator.
    As an example, if you expose the first print with white light at 10
    seconds, the following would be the time for various filters:

    White - 10 seconds
    1 - 15 "
    1-1/2 - 15 "
    2 - 14 "
    2-1/2 - 16 "
    3 - 20 "
    3-1/2 - 25 "
    4 - 50 "

    If a filter was used for the first exposure, then the times would be
    appropriately adjusted based on the above relationships.

    The notes state that the above are for a tungsten light source. They
    also recommend opening up the lens if exposures exceed 60 seconds.
    James Robinson, Apr 22, 2005
  9. iga

    iga Guest

    Thanks a lot to all !
    Best wishes,
    iga, Apr 22, 2005
  10. iga

    Mike King Guest

    Polycontrast filter sets requires exposure compensation for each change in
    filter, PC II and III sets require less compensation from filter to filter
    but changes are still required. The calculator will get you close but
    testing is still necessary.
    Mike King, Apr 24, 2005
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