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Thread: BTZS

  1. #11

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    Quote Originally Posted by roy
    Unless I am missing something here, does this mean that by not using a UV reading densitometer, the assessment of pyro developed negatives is going to be a bit of a "hit and miss" affair ? Or, conversely,can non-pyro developed negatives be assessed more accurately ?
    No, not exactly. You could simply print your pyro stained test negatives directly with your UV process and evaluate the results visually, which is the end result anyway.

    But if you expect to practice sensitometry with UV processes without a UV reading densitometer, then yes, the results, though not exactly a hit and miss proposition, will lack the accuracy we expect from BTZS testing.

    Sandy

  2. #12

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    Here is a copy of the email I just sent to Jorge:
    Hi Jorge,

    Thanks for the feedback. I have attached 2 plotter files. Just curious any observations you may have.

    I recognize some folks are not in agreement on the stained tablet thing! But I can tell you the developing charts from plotter (using stained tablets on paper for ES tests) are consistent with other testing I have employed. Whereas if I had used the ES obtained from the stouffer tablet versus the stained tablet, the charts would be way off compared to my visual experience. Also the speed chart for pyrocat, specifically, is way off. The speed chart for ABC seems OK, and the developing chart seems consistent with my other tests. I have just switched to WD2D over ABC and have little experience with it. Since I have used FP4 for so long with 3-4 developers I certainly can tell if I am selecting the correct speed. I am using the photowarehouse film now. My tests indicate it is FP4.

    Before getting a densitometer I used to borrow one and all my tests were with a zone board, and using HC110 and PMK I had good control. When testing pyrocat in this manner the 0.1 over fb+f tests for speed were misleading and not correct. I then made adjustments after visually assessing the negative. Using 0.1 over fb+f tests for speed, worked quite well for PMK, ABC and HC-110. So it appears I can use the developing charts, but I cannot use the speed data for pyrocat. I can use pyrocat with FP4 at 100 for AZO.

    I appreciate the offer to read some negatives and may ask you to do so in the future.

    On a different note I'd like to read your pmk/pyrocat article and its attendant plotter files.

    thanks

    phil sweeney

    I am seriously considering backing up and using D76 for a while. Everything is about tradeoffs to me and I'd like to have the control afforded by BTZS.

  3. #13

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    Quote Originally Posted by philsweeney
    Here is a copy of the email I just sent to Jorge:


    I am seriously considering backing up and using D76 for a while. Everything is about tradeoffs to me and I'd like to have the control afforded by BTZS.
    Phil,

    When printing with carbon, kallitype and palladium I have found that BTZS gives me very close control of the process. I assume this is due to the fact that these processes are sensitive to such a small band of the spectrum and our UV measuring densitometers are reading in the very middle of this band. So at least with your kallitype work BTZS should work fine, provided that use a densitoimeter capable of UV readings. Or it is possible that you might find a UV filter that cuts off light outside the UV band which you could use with your color densitometer. For exmaple, I use a Wratten 47b filter with my Gretage D200 in Visual Mode and the results are identical to a reading with the X-Rite 810 in blue mode.

    However, if your source of concern is that you can not get the precise control afforded by BTZS with silver gelatin papers, including AZO, with pyro stained negatives I must say that I don't have a solution. The fact of the matter is that the blue filter of a color densitoimeter does not exactly match the paper sensitivity of either regular silver papers or of AZO, plus there is the complication of the light being used to expose the print.



    Sandy

  4. #14

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    Sep 2003
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    Jorge and Sandy: thanks for the help and feedback. At least I know what some of the limitations are and what are the successful experiences of others.

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