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    Re: Obsidian Aqua, catechol staining developer

    Quote Originally Posted by Jay DeFehr View Post
    John,

    Yes, the stain is proportional, and the same brown-ish color as other catechol staining developers.

    Evan,

    In my tests, OA produces a speed increase of about 1/3-1/2 stop over box speed with Low Frequency Agitation, and rotary processing costs up to a full stop, or about 1/2-2/3 stop under box speed. Except for the speed loss, OA is excellent for rotary processing, producing no fog or general stain, and very even development with no streaking or mottling, but it really shines with Low Frequency Agitation, where it produces maximum acutance and compensating effects. But, if you can live with the speed loss, I think you'll be very happy with your results from rotary processing, too.
    I'll try to post an example of OA with rotary processing.

    Thanks, I rate 400 TMY at 320 when metering and Pyrocat MC is one of my developer choices, I always make at least two duplicate sheets. I'll make this tomorrow and compare this weekend..Thanks, Evan
    Last edited by evan clarke; 16-Feb-2012 at 13:38. Reason: Operator error

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