HP-5 vs Tri-X

[Bob McCarthy]

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]

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]

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]

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]

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]

You might enjoy this article, entitled Testing Black and White Film

[Bob McCarthy]

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]

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]

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