Pull processing

[steveo_mcg]

I've been playing with my box camera and nearly finished my only roll of 100 film. I wonder if I could use the 400 stuff I have and pull it at development time? Probably only for the one roll till my next lot of 100 arrives.

This is of course theoretical since I'm still waiting on my changing bag to arrive and its been 15 years since I went near darkroom chemicals.

 

[s162216]

Whilst you could pull it two stops technically, its not usually recommended to go further than 1 as the film tends to start acting strangely and Kodak actually say to not pull a film to compensate for more than a stop of overexposure, if however you want to try, Kodak recommend the basic rule of thumb reducing the development time by 1 minute per stop pulled at 21 degrees centigrade/70 degrees F (and for pushing add on 2 minutes per stop)

Look here under the 'push and pull processing' section for more information. It is aimed towards motion picture films but the same basic principles apply:

motion.kodak.com/motion/uploadedFiles/US_plugins_acrobat_en_motion_support_processing_h2415_h2415.pdf

 

[steveo_mcg]

I wonder if the film has enough latitude to survive being overexposed by two stops and pulled back one stop. Either that or I could just find some fairly subdued lighting.
It's ilford hp5 If that makes any difference.

 

[Jakska]

That should be no problem at all steveo! HP5 has a huge latitude. I've exposed it at 100 before after forgetting to set my meter to 400 and didn't bother pulling the film when processing. It was a slight stretch but I not only got decent prints out of the negatives but decent scans too

A 1 stop should be fine on that.

 

[steveo_mcg]

It looks like I've got away with it. 4 minutes instead of the stated 5, so a 20% reduction. No good reason for that number but seemed to be popular on the web...