Hp5 vs TMY400

[Pere Casals]

I have always used and recommended using HP5 at 200 , some of my clients use it at 160 ISO..

And TMY, to compare?

[Pere Casals]

I don't care how a manufacturer rates their film, or how they go about it, since under field conditions I don't use the methods they do to determine film speed. I use a different developer, developed to a different contrast index,...., and I use what I do because it's how I take photographs. Standard Zone System testing is a long-standing system for practical control of exposure and film development. It's not perfect., but it's seemed to work quite well for a lot of people for a long time. How is this quibbling about method helping anyone?

Peter, there are a lot of ways to meter and to process, so practical film rating is very personal and elastic,

what surprises to me is that with same metering and (I guess) similar processing you find objectively TMY twice faster than HP5, because (at least with xtol) speed point of HP5 it's very close to the TMY one, in lux·seconds units, and both films are well linear from that point...

I'm confident you know what you do with the meter and with the calibration, but I don't understand how you find such an 1 stop difference...

[chris_4622]

Is that the Canham special order price since no one carries 5x7 TMY ? Also would it be more fair, price wise, to compare 320TXP to HP5 ? The price difference isn't as wide then

Yes it was the price from Keith. As I mentioned earlier, the cost difference is significant.

[chris_4622]

Better for portraiture? Well, in my system TMY is twice as fast as HP5+. That allows using a smaller aperture or a faster shutter speed. Both can be important for portraiture.

Thanks for sharing this Peter.

[Vaughn]

Thanks all for this discussion! I have 100 sheets of 11x14 HP5+ that I will be using in Zion in April (tho it is not my goal to use all of it!). It does not easily build up the density range I like to work with, but should work nicely for me with scenes that already have a large brightness range. I'll be using staining developers and perhaps my standard Ilford PQ Universal Developer in some cases.

I have a limited amount of Efke 100IR in 11x14...as well as quite a few fogged sheets (>30) of it that I can use as 11x11, and I like the square. Expired, I rate it at ISO25 and it behaves well. I have FP4+, Acros, and a few others in 8x10 and smaller LF.

[interneg]

what surprises to me is that with same metering and (I guess) similar processing you find objectively TMY twice faster than HP5

Likely to do with the different toes of both films - TMY-II has a shorter toe than HP5+ & if you want to get definitively off the toe and on to the straight line section, that's going to affect your EI.

[interneg]

Yes it was the price from Keith. As I mentioned earlier, the cost difference is significant.

Quickest way to taste them would probably be to shoot a roll of each, widely bracketed & then process to a contrast index in the 0.52-0.58 range, contact print them well & see which general characteristics you prefer. The differences will be pretty obvious side by side, even on a 35mm contact sheet. TXP & HP5+ will be rather closer in character than TMY-II & HP5+.

[Peter De Smidt]

I have always used and recommended using HP5 at 200 , some of my clients use it at 160 ISO..

Bob, I had the same result.

[Pere Casals]

Likely to do with the different toes of both films - TMY-II has a shorter toe than HP5+ & if you want to get definitively off the toe and on to the straight line section, that's going to affect your EI.

Well, we cannot say that HP5 speed point (3.3 stops underexposure from box speed, at red lines) is completely outside the toe, but it's clearly in the good detail zone yet, in fact much better than (rolls) TX400...

[Drew Wiley]

I prefaced my own comment with "high contrast" applications. HP5 will not yield good shadow gradation below Zone 3, TMY will because it has greater native contrast in the toe. In this respect, Ilford box speeds are routinely overly-optimistic. If you're only talking Z 3 to 8 they aren't. FP4 is steeper than HP5, but almost a zone or EV stop less than either TMax film. The other thing I like about TMax is that you can enlarge it a lot more without getting grainy or mushy. HP5 is a great film, but I don't like enlarging it more than 3X. With TMax I can not only use my 8X10, but if there's a nervous portrait sitter, or they want their dog in the shot, I can have a backup MF camera loaded with the same film, or even 35mm with an analogous perspective focal-length lens.