HP-5 vs Tri-X

[wskmosaic]

Is it true that HP-5 does not pull or push as well as Tri-X? I am particularly interested in the pull processing, since I customarily shoot my film at 1/2-to-2/3 of rated ASA.
Warren

[Henry Ambrose]

HP5 might be the most foolproof sheet film there is and its my favorite, but lots of folks like TXP as well.

You should look at the characteristic curves of the films to get an idea of how they compare. The single biggest difference to me is that TXP toes off a good bit, HP5 is straighter at the toe.

HP5 at 250 or 320 is gonna be great, just adjust your development time to hold onto the highlights. I wouldn't call this rating a pull or push, cause it's not. It's the real world speed.

[ki6mf]

Ditto on Henry's comments I shoot HP 5 at ISO 300 and use D76 diluted 1/3 Developer 2/3 water. Normal development times is 14 minutes with 2 minutes less development for each stop of over exposure, highlights more than 5 stops over textured shadows. It works great. Other developers when tested can give comparable results in terms of tonal range. With most scenes with sun shinning I usually develop around 8 minutes

[mcfactor]

I agree about Hp5, it is really hard to mess up. And it does push very well. I have shot it at 1600 developed in Beutler's 1:1:10 and had very good results.

[Vaughn]

HP5 does not push well for alternative processes, which is the extreme case. I am referring to negatives that have too much contrast to even think about silver gelatin printing. Both FP4 and Tri-X are better in that regard.

I need to test HP5 in a high contrast developer such as D-19 someday.

[wskmosaic]

For what it's worth, I did get this reply from Ilford regarding extended indices for HP-5:

Essentially Tri-X and HP5+ share very similar characterstics in terms of exposure latitude both for under and over exposure. We haven't published development times for "pull" processing as under regular lighting conditions we don't believe that this is the best use of the film. The majority of users purchase HP5+ for its ISO 400 speed and the ability to push process well past this for use in low light. This is not to say that you cannot do this, and I could see a possible reason to do this if the lighting conditions were extremely contrasty, or of course, if the film had been mistakenly rated at a lower speed

For EI 200 I have found a time of 14 mins @ 68f in IDII @ 68f. Also in DD-X at 1+4 of 7 mins @ 68f.


Thanks to all for your help
Warren

[Andre Noble]

"I usually shoot my film at 1/2 to 2/3 of rated ASA"...

One should always shoot B&W film at 1/2 to 2/3 of rated ASA. This is not a situation for "pull" processing, by the way. Manufacturers optimistically over rated their films by one stop on average.

[Bob McCarthy]

"I usually shoot my film at 1/2 to 2/3 of rated ASA"...

One should always shoot B&W film at 1/2 to 2/3 of rated ASA. This is not a situation for "pull" processing, by the way. Manufacturers optimistically over rated their films by one stop on average.

Certainly was true with Tri-X. ASA<G> 200

Though I'm rating TMax at full speed.

bob

[Drew Wiley]

Push and pull are really lab terms. I'm more comfortable with the Zone concept of plus
or minus dev. But everything depends upon the range of the subject you actually want
to reproduce, the capabilities of your print paper, dev, etc. In normal situations, cut
the speed of TM100 in half and you're very likely to blow out the highlights (throw them onto the shoulder of the curve). By contrast, use HP5 in a "normal" contrast scene at full speed, and you'll probably lose differention in the deep shadows - it has
more toe than TMax films, as does Tri-X. This said, I broke the rules a lot - overexp and overdev the HP5 in pyro, then added a silver contrast mask - that way I got to
keep my cake and eat it too: beautiful etched edge effect, good shadow value separation, magnificent midtone and highlt separation, and close to full speed, plus that lovely "watercolor" grain effect HP5 is known for in pyro (as opposed to the gritty
salt and pepper effect of Tri-X). Nowadays I tend to be more lazy, and find that
TM400 lands me pretty much where I want to be without a supplementary mask.

[corgan4321]

One should always shoot B&W film at 1/2 to 2/3 of rated ASA.

I don't know if I agree with this. Do you really think TMX100 is better shot at ASA 50? As it is, I get super contrasty negatives developing at the suggested times. Anyway, if I rated my TMX100 at ASA 50, I'd be overexposing and would end up with less contrasty negatives.