HP5+ rodinal testing

[mikeb_z5]

Hi all,
I just finished running some tests on hp5+ with rodinal 1+25 tonight and found my results a little confusing. I hope you guys can shed some light on my findings.

I am using a 4x5 stouffer 21 step wedge as described in noseoil's article posted in the how to area.

1. I shot the first exposure to establish a film speed and settled on rating at iso 100(developed 1+25 8min@68f using agfa recommended time).

2. shot 4 more sheets at iso 100 and developed in trays(constant agitation 15ml rodinal, 375ml distilled water) 1+25 for 7min, 8min, 10min, and 12min @ 68f to determine highlights.

the 7min development revealed n-2
the 8min development showed n-1 1/2
the 10min development showed n-1
the 12min development showed n-1

a slight increase in film speed(1/2 stop) occurred from 7min-12 min development. No problem there, I expected that.

Are these result normal for Rodinal? the curve appears to be basically flat.
Could I really need to develop for 20min+ to obtain N development? or more for n+?

I am thinking that by increasing development times further to try to obtain N development times I will be chasing film speed forever.

I'm not questioning the testing procedure as I have performed tests with HP5+ and tri-x in XTOL recently with results as I expected.

Any thoughts on this? Is hp5+ and rodinal just not compatible?
I am hoping to test tri-x 320 with this developer next and eagerly await your replies.

Please don't suggest I just forget about it and just go shoot some film . I am just trying to get a handle on the rodinal thing and some reasonable development times. I am not a testing junkie

Thanks,

Mike

 

[Lee L]

I don't have any good guesses at the problem, but an EI of 100 seems low. I'd expect something on the order of EI 160-250 with HP5+ and Rodinal at normal development.

Lee

 

[rduraoc]

I shoot HP5+ in 35mm with iso 200 , so it might differ, but in Rodinal 1+25 @20ºC I had a time of 8 min. I'm now trying to use rodinal at 1+50, but still haven´t reached a good time.

 

[Thomas Bertilsson]

Possibly exhausted developer?

Is it possible that you're exhausting your developer?

 

[Lee L]

Is it possible that you're exhausting your developer?

I considered that as well, but at 15ml of concentrate to four 4x5 sheets of film, that doesn't seem very likely.

Lee

 

[mikeb_z5]

I thought about the exhausting also. The data sheet is not clear on how much concentrate to use. But I figured since my normal developing tank for 35mm holds about 400ml of developer I would be in safe territory with this amount.

As for the iso 100 rating, it seemed to be dead on for the n-1(10 min) development time.

I think I'm going to reshoot at 160 and see what happens.

I can see why some gripe about testing film/developer combo's now

Mike

 

[JackRosa]

Rodinal = one shot developer.

Naturally, my results will be somewhat different from yours because we have different meters, different lenses, different shutters, different cameras, but ...

I rate HP5+ at 250 and achieve normal (N) development at 6 minutes at 70 degrees F. The times you speak of seem very long.

The above using 8x10 negatives and developing them in trays with first minute constant (gentle) agitation and then 5 sec. gentle agitation every 30 seconds.

 

[Jorge]

The Rodinal gods are fickle, I did a test with Ultrafine 125 and could not get any expansion at all. I dont know what happened but it seems the developer exhaust readily, at least in tube development.