Looking for Filter Factor

Discussion in 'Darkroom Developing and Printing' started by Daniel Williams, Jun 18, 2005.

  1. I am looking for the filter factor for a Tiffen Orange 21 filter. I
    tried their website and a Google search but haven't been able to come up
    with it.

    Dan Williams
     
    Daniel Williams, Jun 18, 2005
    #1
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  2. Daniel Williams

    Peter Guest

    My Tiffen "Filter Facts" booklet (used to come with the filters, I
    think
    I've got several of them) lists a 2 1/3 stop increase for the #21
    filter in daylight and a 2 stop increase under tungsten light.

    This equates to a filter factor of 5 for daylight and 4 for tungsten.
    These figures are for the older style panchromatic films. Some
    modern films such as the T-Max series have less excess blue
    sensitivity and permit lower filter factors for yellow and orange
    filters.

    If you want to capture shadow detail on a day with clear blue skies,
    you may need a bit more exposure with an orange or red filter
    than the usual filter factor suggests, because the shadows can
    have a definite blue cast. This is also the reason why an orange
    or red filter appears to increase the contrast between light and
    shadow.

    If you want a dramatic sky, and are prepared to sacrifice some
    shadow detail, then a slight underexposure can help.

    It is best to experiment a bit. Run a series of exposures both
    with and without filter and find out what works for you.

    Peter.
     
    Peter, Jun 18, 2005
    #2
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  3. Peter,

    Thank you, that is what I was looking for.

    Dan Williams
     
    Daniel Williams, Jun 18, 2005
    #3
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