As I get more organized, I am starting to create some push/pull times for development based on film stock and developer. These calculations are related to developing sheet film in a large tank or tray. Development times for small formats (35mm / 120) will be different. I plan to update with more stocks and chemical recipes as I go. In the charts below, n is the recommended normal development time at 68°F. The +/- of n is the amount needed to push/pull based on the Zone Metering difference between highlights and shadows (roughly 20% per). There are many methods for determining the n and many variances within similar methods. So, you may read many different things on the web. But this is how I have been doing this, and I have been very happy with the results.

All things being equal (not accounting for other development factors) this is how I develop:

  • if highlight zone - shadow zone = 5, then develop at n-1 (high contrast adjustment).
  • if highlight zone - shadow zone = 4, then develop at n.
  • if highlight zone - shadow zone = 3, then develop at n+1 (low contrast adjustment).

For more details on n calculations, you can see my post on pulling HP5 for more details.

Kodak D-76 (stock) 68° | Large Tank 

Delta 100 HP5+ 400 Tri-X Pan TMAX 400 TMAX 100
n-3 3:36 3:00 2:54 4:00 2:54
n-2 5:24 4:30 4:21 6:00 4:21
n-1 7:12 6:00 5:48 8:00 5:48
n 9:00 7:30 7:15 10:00 7:15
n+1 10:48 9:00 8:42 12:00 8:42
n+2 12:36 10:30 10:09 14:00 10:09
n+3 14:24 12:00 11:36 16:00 11:36

Ilford Ilfosol 3 1+9 68° | Large Tank

Delta 100 HP5+ 400 Tri-X Pan TMAX 400 TMAX 100
n-3 2:00 2:36 3:00 2:24 2:12
n-2 3:00 3:54 4:30 3:36 3:18
n-1 4:00 5:12 6:00 4:48 4:24
n 5:00 6:30 7:30 6:00 5:30
n+1 6:00 7:48 9:00 7:12 6:36
n+2 7:00 9:06 10:30 8:24 7:42
n+3 8:00 10:24 12:00 9:36 8:48

Kodak XTOL (stock) 68° | Large Tank 

Delta 100 HP5+ 400 Tri-X Pan TMAX 400 TMAX 100
n-3 3:00 3:12 3:00 2:36 3:18
n-2 4:30 4:48 4:30 3:54 4:57
n-1 6:00 6:24 6:00 5:12 6:36
n 7:30 8:00 7:30 6:30 8:15
n+1 9:00 9:36 9:00 7:48 9:54
n+2 10:30 11:12 10:30 9:06 11:33
n+3 12:00 12:48 12:00 10:24 13:12