wow thanks juan valdenebro, that is a great starting point, to develop the hp5 I will definitely try like that Is the developer beutler really identical to the neofin blau?
It also depends on the type of light: the type of scene contrast... I expose HP5+ from EI100 to EI3200, and this is common... Between 100 and 200 for direct sun with a shorter development; from 200 to 800 for overcast (soft light); from 800 to 3200 for pushing...The answer to your question is not a time, but doing a couple of tests using a roll of film... You can do it for overcast and for sun... I'd do this:
Sacrifice one roll: half of it for getting information about soft light, and the other half for seeing what happens under direct sun...
For soft light you can expose half the roll repeating the same scene at 200, 400 and 800: repeat that, until half the roll... Then wait for direct sun and do a sunny scene at 100, 200 and 400 until the roll is over. Then, in darkness you cut the film in two and place the first half inside the black plastic can HP5+ comes in, and mark that can "soft 200-400-800", and place the second half in another black can labeled "sun 100-200-400": then you have enough material to test...
Then you cut every half in three, and place the three parts inside each can...
Develop normally, spending the normal amount of developer used for a roll, one of the soft light pieces of film using the time I gave you: you'll decide after that first development if you prefer the next one more or less developed: you got two more strips to fine tune...
When you have YOUR time for overcast, start the sun test using a time 25% shorter, and take a look on paper if you wet print... Again, you have two more strips to develop differently:
You spend a roll, a day, and some developer, but you will KNOW for sure what your system needs...
Bye