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  1. #1
    BetterSense's Avatar
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    Finding starting point developing time without data

    I recently switched to d23 and found it hard to find development data compared to d76. I actually went to the MDC and made a spreadsheet comparing average ratio of d23 times to d76 times so I would have some idea where to start on films like Acros that have no data available (I found that about 75% of the d76 1+1 time was average for a d23 time). Even Kodak datasheets don't give d23 times.

    There is a simple dip test to determine the approximate development time in any developer. This can be used to refine your results down to the best practical value for any developer.--Photo Engineer
    I don't mean to call out Photo engineer specifically but I've never heard of such a test. How is it conducted?
    f/22 and be there.

  2. #2
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    Hi,

    I hope what I'll say makes sense, otherwise I'll just hide for a while ;-)

    IIRC, the dip test is simply to dip a piece of film (leader from a 35mm cartridge for example) in the developer, and see how long it takes to get the max. black. This should at least give you a basic idea of the time needed.

    Hope this helps
    Laurent
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  3. #3
    Ian Grant's Avatar
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    At one time D23 times were listed being the same as for D76, so that's your starting point.

    Ian

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    Hello.
    There's an old technique (could be the same dip test mentioned by PE):
    - take a small strip of film you want to test;
    - put it halfway in the developer and start the clock;
    - stop the clock when the part in the developer reaches the same colour as the part outside (it is lighter at first and then begins to darken);
    - multiply the time you measured in seconds by 17,5 and divide by 60 to get your development time in minutes.
    For example: measured time 25 sec * 17,5 = 437.5 sec / 60 = 7.3 min development time. This should give you a good starting point.
    It can be also quite useful for people who like to experiment with different dilutions.

  5. #5

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    bettersense

    you might also consider getting a darkgreen safelight
    and learning how to DBI ( develop by inspection )
    i often do this with sheet film, and have done it a few times
    with 125 and 120 ... it is not to hard to learn this technique,
    and may be very helpful.

    there is a great article here:

    http://www.michaelandpaula.com/mp/devinsp.html


    thanks for writing about " the test" aleckurgan !
    i had never seen that.
    lights on or off ?
    ( sorry i am not a master of the obvious sometimes! )

    john
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  6. #6
    Photo Engineer's Avatar
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    Laurent's post says it all.

    PE

  7. #7

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    Quote Originally Posted by jnanian View Post
    thanks for writing about " the test" aleckurgan !
    i had never seen that.
    lights on or off ?
    ( sorry i am not a master of the obvious sometimes! )
    john
    Of course on! Otherwise you won't see the difference between wet and dry parts.

  8. #8
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    hallo

    my scetchbook says acros with d-23 1+1 for 15 minutes gives a good result (rollfilm)

    are you using d-23 oneshot or more than one time?
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  9. #9
    Photo Engineer's Avatar
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    Quote Originally Posted by aleckurgan View Post
    Hello.
    There's an old technique (could be the same dip test mentioned by PE):
    - take a small strip of film you want to test;
    - put it halfway in the developer and start the clock;
    - stop the clock when the part in the developer reaches the same colour as the part outside (it is lighter at first and then begins to darken);
    - multiply the time you measured in seconds by 17,5 and divide by 60 to get your development time in minutes.
    For example: measured time 25 sec * 17,5 = 437.5 sec / 60 = 7.3 min development time. This should give you a good starting point.
    It can be also quite useful for people who like to experiment with different dilutions.
    Sorry, but this test does not make sense to me.

    The part outside the developer will not darken or change at all, and the part inside the developer will darken. The part outside the developer is not even developing, it is raw emulsion.

    Or did I misunderstand something?

    PE

  10. #10
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    Quote Originally Posted by pcyco View Post
    hallo

    my scetchbook says acros with d-23 1+1 for 15 minutes gives a good result (rollfilm)

    are you using d-23 oneshot or more than one time?
    I usually use it replenished, but I have another batch for use with dilutions or films that stain my replenished developer (foma/edu.ultra). Thanks for the data. Is that at box speed? I'm going on a trip soon and will probably shoot up some acros.
    f/22 and be there.

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