Need testing clarification please

Discussion in 'B&W: Film, Paper, Chemistry' started by coops, Jul 29, 2009.

  1. coops

    coops Member

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    I just read an article on doing testng for finding the proper proof time (minimum time for maximum black), finding personal exposure index, and normal developing time.
    Proof time is straightforward. Regarding exposure time, if shooting say a 400 speed film, and the best of 6 negatives exposed at different speeds, the one that prints just slightly lighter than the papers maximum black is at a speed of 200, I assume I shoot that film at that speed from now on, as long as I am consistent with developing and printing techniques?
    Regarding normal development time, I shoot six sheets of film of say a zone 7 range, and develop for 60%, 80% through to say 130% of the developer manufacturers time for a given developer, temp etc I am looking for a negative that prints slightly lighter than the white paper, and that is my ideal developing time.
    So lets say for the paper I use, my minimum black is 20 secs, and the film speed I use is 200 and 8 mins is my developing time. In practice, if I meter zone 3, and then zone 7, develop my film at 8 mins, I should have a good negative (assuming I metered correctly) that should proof well at 20 seconds with my paper. And I can use the negatives I used for testing on other papers and record minimum time/max blacks etc?
    Is this basically correct, or am I missing something?
    I want to do this this weekend, so any help is appreciated.

    Thanks
     
  2. ic-racer

    ic-racer Member

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    That all seems OK.
     
  3. sun of sand

    sun of sand Member

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    I'm about to hit the sack but slightly lighter than paper white is not available
    You need "slightly darker" here
    zone 8 or whatever zone needs to be matched by development time
    zone 8 = zone 8 and not zone 9 or 10
    zone 8 should be darker than paper white
    Zone 9 is probably barely perceptible so zone 8 has some real tone to it

    I'm not that anal about it so I just guess/approzimate zone 8 tone ..could be zone 8.5 or 7.5


    EI is tone slightly darker than film base -Zone 1
    Barely -I mean barely- perceptible tone isn't quite enough density to make it onto the print aper and so lower EI needed
    The difference between EI of 50 and 64 is? I doubt you could meter perfectly to be sure tones you want are present -or visualize a scene perfectly for print- so either or is good enough but asince overexposure is better than underexposure ..be safe and go with 50 ..the neg with easily noticable darkening over clear film base
     
  4. sun of sand

    sun of sand Member

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    You could probably also test EI for overcast and ssunny days or golden hour times and mountain/shade light and filters and lenses -coated vs uncoated etc as they _might_ need slightly different exposures

    Well, if you're anal
     
  5. coops

    coops Member

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    Thats what I meant to say, slightly darker.

    Thanks for the response