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  1. #41
    Greg Davis's Avatar
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    I just tested a Thomas Duplex safelight with the color filters installed. It has a new bulb, new B&W FBD filters in the base, and new FCD filters in the vanes with the vanes fully closed like the instructions say, and even with 5 minutes exposure it does not fog the paper from 4 feet away. The safelight is bright enough to barely see the opposite side of the darkroom which is 12-14 feet away. I can easily see any trays or boxes in there. Since this is in a school environment, and the darkroom is for B&W mostly, both classes can work in the same room at the same time with some level of visibility.
    www.gregorytdavis.com

    Did millions of people suddenly disappear? This may have an answer.

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  2. #42

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    I don't see where anyone mentioned it, but for Type-R (Reversal) and Ciba, no safelight can be used. For Type-C paper, you can use the filter PE mentions, the WR13, and it is actually pretty bright.
    Kirk

    For up from the ashes, up from the ashes, grow the roses of success!

  3. #43
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    That is correct Kirk and a good point. Reversal film dyes have no "hole" in them spectrally and therefore the paper for printing them must be full panchromatic. Negative films do not have to be viewed by the human eye and have a hole built in for maskig and therefore the paper can work around that by having a "hole" in the sensitivity. This emphasizes the big difference in dyes for reversal and negative films.

    Negative films usually use Status M filters for reading sensitometry while reversal films usually use Status A. These match the dye types. Papers usually use Status D. These are commercial designations of filter sets for color densitometers.

    PE

  4. #44
    Greg Davis's Avatar
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    I should have mentioned that I was testing the safelight with RA4 materials. Kodak Endura showed no fog after 5 minutes of exposure to the Thomas Duplex with teh proper FCD color filters installed.
    www.gregorytdavis.com

    Did millions of people suddenly disappear? This may have an answer.

    "No one knows that day or hour, not even the angels in heaven, nor the Son, but only the Father." -Matthew 24:36

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