TMY only 320 in HC110?

I was looking through the tmax datasheet today and noticed they recommend rating the film at 400 for all their developers listed except when using HC110, they recommend rating at 320. This, despite that most people say HC110 is equivalent to D76 in most respects. I haven't heard of HC110 being a speed decreasing developer. Is this specific to TMY?

I would bet that if you ran BTZS tests on both those developers TMY would come in closer to 200 for a normal dev time.

BetterSense said:

I was looking through the tmax datasheet today and noticed they recommend rating the film at 400 for all their developers listed except when using HC110, they recommend rating at 320. This, despite that most people say HC110 is equivalent to D76 in most respects. I haven't heard of HC110 being a speed decreasing developer. Is this specific to TMY?

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If you look at the characteristic curves for the various Kodak films in the Kodak data sheets, you will most likely observe that HC-110 dil B builds contrast as much or more than any of the other combinations. For those other films, there isn't seen to be a need to increase exposure and reduce development to take this into account. I expect though that TMY's ability to record very high highlight exposure, with unusually high contrast in those highlights, causes Kodak to recommend a bit more exposure and a bit less development with TMY than with other films. It is still an ISO 400 film - Kodak is just stating that optimum results are obtained at an EI of 320.

People on APUG (and elsewhere) always seem to focus on shadow detail when considering how to rate film. Kodak's recommendations also take into account highlight rendition.

It is for similar reasons that Kodak recommends exactly the same development time for TMY exposed at 800 as TMY exposed at 400.

It seems counter intuitive that they would recommend more exposure for a developer that builds highlight contrast faster.

HC110 also has a reputation for low fog which I think of as helping shadow speed but maybe not.

Every time I see that chart, it makes me want to switch back to Xtol.

BetterSense said:

It seems counter intuitive that they would recommend more exposure for a developer that builds highlight contrast faster.

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They recommend more exposure + less development for just this reason - HC-110 builds highlight contrast faster.

TMY-2 exposed at 400 gives really good results when developed in HC-110 dil B.

TMY-2 exposed at 320 gives optimum (i.e. slightly better) results when developed in HC-110 dil B.

X-Tol is a great developer.

Depends on developer concentration as well as time/time/agitation. You have to be specific about which HC-110 dilution you're discussing. I personally have no problem with full box speed (400).

I usually use 50:1 for about 9 minutes at 20C agitating every minute. I'm not going to stop using HC110 because I am trying to standardize but it's too bad it's not optimum with the film I was also trying to standardize on (tmy). Maybe I should standardize on Rodinal instead

I use HC-110 dil E replenished, but otherwise in a very similar fashion with TMY-2.

I think you may be overly concerned with "optimum". Here is an example

Do your own testing before you make up your mind. As always your mileage may vary ! Black and white is a very flexible medium and bending the rules is fun and educational. The difference between 400 and 320 is less than most folks metering errors anyhow.

MattKing said:

I use HC-110 dil E replenished, but otherwise in a very similar fashion with TMY-2.

I think you may be overly concerned with "optimum".

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Dilution E "replenished"??? My dilution E goes right down the drain.

Curse Kodak and their arcane letter dilutions! I really wish people would just say "1:63" so I didn't have to go Google the dilution definitions.

BetterSense said:

Curse Kodak and their arcane letter dilutions! I really wish people would just say "1:63" so I didn't have to go Google the dilution definitions.

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Dilutions A, B, C, D, E, F and G were easier to deal with when people were communicating with semaphore and teletype .

Back in the day, when you were using HC-110 in your commercial lab and choosing a different dilution for each of your six processors (to mimic six different special purpose Kodak developers, or to adapt to the pecularities of those processors and the developers they were designed for) the nomenclature worked very well.

I just keep a link to J-24 always at hand: http://www.kodak.com/global/en/professional/support/techPubs/j24/j24.pdf

And remember that so called dilution H is half as strong as B.

I don't believe in 320.

miha said:

I don't believe in 320.

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Me neither I set the meter to 200.
If you underexpose a stop you have clear negative where you might have had printable detail.
Under exposure is like Russian roulette with a 1911a1!

At an EI of 320 we are talking about a third of a stop which is hardly earth shaking. There is more slop in many mechanical shutters than that.