is it my process or do 120 and sheet film require different exposure/developement?

I have started shooting 4x5 over the last few months and enjoying it. but I am having issues with differences between 120 film and sheet film. mainly its with delta 100. all my other films have no issues.

I have my EI and development worked out for all the films I use in 120. so I used that as a starting point for the same emulsion in 4x5 and all seem fine, maybe a little more contrast with the sheet film, but exposure/development seem very similar or similar enough to not make a big difference. but not so with delta 100. when I use my 120 settings (for lack of a better descriptive) all the sheets I shoot with all the lenses seem to be over exposed or over developed by at least 1 stop. I have only shot 12 sheets, but they are consistent. are there differences between ilford roll and sheet emulsions? I guess i have to do some testing, which is a drag, but i guess needed. for 120 I shoot at EI of 64 and develop in pyro-m 72 degrees for 15 minutes. 1 min initial agitation and then 10 seconds every 3 minutes.

so is it me or is there a difference?

thanks
john

FWIW, here are my notes for Delta 100:

1) For 4x5, I shoot it at EI 80 and develop in a Jobo Expert Drum, F76+ at 1:14 for 5 mins @ 75F on speed 4

2) For 120, I shoot it at EI 64 and develop in a small tank, F76+ at 1:9 for 5 1/2 mins @ 68F, continuous agitation for the first 30 secs, followed by 2 inversions every 30 secs thereafter.

This is all based on sensitometric testing, but since I don't use the same dilution of developer or the same developer temp I can't be certain how different, if at all, this really is.
Anyway, I hope this helps.

Emulsion is the same, should work the same, if film is fresh.

Check your LF shutters, use a shutter tester.

My bet is that there's an issue with one of your two cameras and not your development technique.

well, i assume shutters are good because all my slide film and every color neg and B&W film comes out perfect. I guess Ill just do some testing and deal with it. its not like its a big deal, it was just a little surprise, thats all.

destroya said:

Ill just do some testing and deal with it

Click to expand...

You may use a roll film back in the rear of the view camera to check that both formats behave the same.

Personally I've never noticed a difference with fresh film.

Roll film and sheet film and their associated camera systems can incorporate significantly different amounts of flare, and of halation.
And sheet film agitation is usually at least a bit different than roll film agitation.
All of those factors could lead to different EIs and contrast,
But I would suspect that the differences in lenses, apertures and shutters would be more important.

have you noticed a difference between other films or is it just delta >
my guess is the LF shutter is a litttle slow so it over exposes
and the MF one is right on seeing your chromes are good with MF..
have fuN !
john

To eliminate the differences in camera system and agitation playing a role, you might want to 1) use a roll film back on your 4x5 system as suggested by 138S and 2) use Taco method to develop 4x5 sheets in the daylight tank with identical agitation scheme.

just delta. I have used the same film in sheets and roll film with a roll film holder. I used velvia 50 to check, think it would show exposure differnces the most. they both came out the same. same with HP5 and FP4

again, its not a big deal, just one more thing to think about before tripping the shutter. I dont shoot delta in 120, I use tmax 100 or fp4. but the huge price difference in sheet film between kodak and ilford, I started shooting delta 100 and HP5. the HP5 comes out the same.

john