Pushing HP5+

Discussion in 'Film and Processing' started by scottlaursen.com, Jan 24, 2021.

  1. I normally rate HP5 at 200 and develop per 400 times. I pushed it to 800, thinking development would be N+1, now I am wondering if it should actually be N+2 since I normally rate it as 200? Input is appreciated.
  2. AJG


    If you're happy with your results at 200 with the 400 time, then probably N+1 would be the way to go. If this is important, once in a lifetime work, then shoot and develop a test roll to see if you like the results.
    scottlaursen.com likes this.
  3. thanks! It is not important lifetime work. I live in Michigan's UP and just have not seen the sun for weeks, so I thought I would give push processing a try for a bit most contrast.
  4. All that changing the development time does is to alter the contrast (maximum density) of a negative.

    Unless the film is severely underexposed (which 1 measly stop isn't), such a change in Dmax and 'slope' can mostly be easily compensated by using a different paper grade or in post-processing after scanning.

    In short: An N+1 development will be plenty.

    Here are the curves of 100 and 400 ISO films at different (push-pull) development times.
    You can see that the 'toe' of the curves stay quite firmly put on the X axis. Whereas if there was a true effect on the film speed the curves would move to the left with increasing development time.

    In other words, nothing you do to the development time affects the speed of the film at all.
    Last edited: Jan 25, 2021
    scottlaursen.com likes this.
  5. Thank you.
  6. For Tri-X and TMY, Kodak recommends the same times for EI 400 and 800.

    That is, they believe it has enough latitude to do either one with those times.

    I didn't look up HP5, but it is probably reasonable for that, too.

    Otherwise, if I wanted HP5 at 800, I would use Diafine.

    Well, I now have DIafine, HC-110, and TMax developers, though for the latter two I usually mix up enough for more than one roll.

    HC-110 is a favorite for older films, and TMax for the higher push speeds of TMZ and Delta3200.
    Last edited: Jan 26, 2021
  7. I find HP5 pushes beautifully to 1600 and even 3200 in DDX and Microphen.

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