Pre-flashing with dry-down exposure compensation

Discussion in 'Enlarging' started by Sim2, Nov 22, 2009.

  1. Sim2

    Sim2 Member

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    Hallo to you all,

    The dry-down factor of a paper is programmed into the RH Designs Stop-clock professional with great success in retaining the highlight details.
    The pre-flash time of a paper with the RH Designs pre-flasher has been established as the time shorter than the one that displays the slightest tone on a dry blank print.

    The pre-flash is used to bring down a highlight to the required tone without extending the exposure time with the consequence of "blocking up" the shadow areas, in other words – when using the pre-flash the detail is retained in a shadow area whilst the highlight is brought down off paper white into a detail tone. This is done on test strips without the dry-down factor.

    When the actual print is made the dry-down factor is programmed into the timer, but not into the pre-flasher.

    Should the pre-flash be reduced by the same dry-down percentage?
    How can a percentage be put into the RH Designs pre-flasher when the times are in f-stops?
    What are your routines with dry-down and pre-flash times?

    Your thoughts/considertions welcomed!

    Sim.
    *no affiliation to RH Designs other than a happy customer*
     
  2. Blighty

    Blighty Subscriber

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    The easiest way to find the correct print exposure (taking into account flash exposure and dry down times) is to make a test strip of your neg on an already flashed piece of paper. Dry your test strip with a quick blast in the microwave (I'm not kidding!) if you're using FB paper or a hairdryer if it's RC and then judge the results. I automate the process a little by using an RH Designs Zonemaster II calibrated for use with my RH Flash which gives me the correct 'sub threshold' flash time. If you can't be arsed with all this palaver, you could simply reduce the flash exposure by one or two steps below normal and see what happens. Regards, B
     
  3. Sim2

    Sim2 Member

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    Thanks. Guess that I might have to try it at two steps below the threshhold. Just wasnt sure if anyone else had an answer/procedure for this!

    Dont think the microwave in the kitchen will be used for paper drying though....

    Sim.
     
  4. RalphLambrecht

    RalphLambrecht Subscriber

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    Why not, works well. I use it for FB test strips!
     
  5. Sim2

    Sim2 Member

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    I am sure that it a microwave does work well for drying paper - just not sure about using the same microwave for cooking and print drying!
     
  6. RalphLambrecht

    RalphLambrecht Subscriber

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    I have no choice. We only have one microwave. I always do it when she is not watching. :wink:
     
  7. Ed Sukach

    Ed Sukach Member

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    Nothing new. I have a video tape where Ansel Adams - the great St. Ansel, himself, does exactly that as a matter of course - drying a portion of a print in his microwave for evaluation.