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wskmosaic
2-Aug-2010, 09:59
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
2-Aug-2010, 10:22
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
2-Aug-2010, 18:19
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
3-Aug-2010, 06:45
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
3-Aug-2010, 08:34
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
3-Aug-2010, 08:53
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
3-Aug-2010, 09:48
"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
3-Aug-2010, 11:19
"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
3-Aug-2010, 12:07
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
4-Aug-2010, 12:16
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.

Bob McCarthy
4-Aug-2010, 18:15
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.

I think the suggestion included the assumption of reducing development times to get the appropriate density. This would lower contrast.

With regards to Tmax 100, with my meters, and where I point it, etc, I get 100 as normal with adequate shadow density.

Your experience may vary.

bob

D. Bryant
5-Aug-2010, 09:36
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.

HP5 will work fine for alt processes if a staining developer is used. In fact stained HP5 works very well for ferric based processes such as VDB or plt/pld. It may not be optimum for carbon printing, but there are those that use stained HP5 for that too.

Don Bryant

corgan4321
6-Aug-2010, 18:10
I think the suggestion included the assumption of reducing development times to get the appropriate density.


Interesting, how would one calculate the decrease of dev time after shooting 1/2 to 2/3 the rated ASA?

Henry Ambrose
6-Aug-2010, 19:10
Interesting, how would one calculate the decrease of dev time after shooting 1/2 to 2/3 the rated ASA?

About 20% less time is a starting point.

You could do a test, read the film and chart the changes in densities. It'd be a lot of work.

ki6mf
7-Aug-2010, 04:08
The most important thing in all of the process is to Test, measure, record results, not change chemistry during this process! You will be changing variables like dilution of developer, time of development, etc to get the results you want. Never change mid way through the process, for example let me try a new developer or new diution, unless you start over from the beginning with the new materials!

Ken Lee
7-Aug-2010, 08:13
You might enjoy this article, entitled Testing Black and White Film (http://www.kenleegallery.com/html/tech/testing.html)

Bob McCarthy
7-Aug-2010, 09:39
Interesting, how would one calculate the decrease of dev time after shooting 1/2 to 2/3 the rated ASA?

I think you got some great answers. In the end it comes down to exposure controls shadow density, development controls the density of the highlights. The later is highly dependent on how you transfer the info from the negative. either enlarger ( and there are different requirements depending on the light source of the enlarger) or scanning device, or I suppose contact print material also...

So there is no exact number. If your happy with your shadow density, you've nailed your iso for your equipment. If the negative is too contrasty for your print method, shorten time, too flat then lengthen.

So the real answer is : it depends....

Its what makes a good printer - great, well better anyway....

Then it up to you to be a great photographer.. With the skills to get your vision on print

Bob

Vlad Soare
9-Aug-2010, 22:48
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.
Vaughn, I hate to disagree, but I have just made a couple of vandyke prints from HP5+ developed (in fact severely overdeveloped) in ABC Pyro diluted 1:1:1:7. They are extremely contrasty, with highlights almost bulletproof, but they still retain very fine details, which are perfectly visible on the lightbox (though probably impossible to print on a silver halide paper).
In fact, the first picture is a bit too contrasty even for vandyke. My daughter's white dress shows perfect detail on the negative, but I couldn't print it without sacrificing the shadows.
In the second picture the subject was very flat. The overall brightness range was just about two stops. And yet ABC Pyro managed to raise the highlights enough to print well even on vandyke, let alone silver halide. I'd call that a quite decent push... :)

wskmosaic
11-Aug-2010, 11:37
About 20% less time is a starting point.

You could do a test, read the film and chart the changes in densities. It'd be a lot of work.


I believe Ilford's tech sheets give you approsximates that are pretty good--at least as starting points.
Warren