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Thread: Pyrocat-HD & densitometer reading??

  1. #1
    Bob Farr's Avatar
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    Pyrocat-HD & densitometer reading??

    Hi,

    My question is; "What density readings should I be getting with HP5 and Pyrocat-HD??"
    I've just completed a film test with HP5 and Pyrocat-HD [1:2:100] at 75 degrees using BTZS tubes. Developed for 5, 7, 10, 15 and 20 minutes.

    Am using the blue channel on my 310 X-Rite. The densitometer was completely rebuilt by X-Rite 3 years ago and calibrated before reading the film densities.

    The Dmax for each are as follows; 0.31, 0.38, 0.45, 0.52 & 0.57.

    These seem rather low and was wondering how they compare with what others have experienced??

    Thanks,
    Bob

  2. #2

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    Re: Pyrocat-HD & densitometer reading??

    Bob,
    Are these reading transmission Dmax? If so, something is wrong as they are way, way off. A blue channel reading of HP5 in Pyrocat 1:2:100 for 20 minutes at 75F should give a reading of over log 2.5.

    Sandy
    http://www.sandykingphotography.com/
    For discussion and information about carbon transfer please visit the carbon group at groups.io
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  3. #3
    Bob Farr's Avatar
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    Re: Pyrocat-HD & densitometer reading??

    Hi Sandy,

    I questioned my readings. My assumption and hope is that the densitometer is incorrect.

    Thanks,
    Bob

  4. #4

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    Re: Pyrocat-HD & densitometer reading??

    Do you calibrate with a step wedge?

  5. #5
    Bob Farr's Avatar
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    Re: Pyrocat-HD & densitometer reading??

    Hi Paul and Sandy,

    Realized that I'd calibrated the densitometer incorrectly. So, I now have a Dmax, step 1, of 2.46 on HP5, P-HD [1:2:100] at 70 degrees F.

    Thanks to both of you for helping me with this.

    Cheers,
    Bob

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