Speed difference between Acros II, TMX, and Delta 100 at same CI?

[Augustus Caesar]

Sounds like a Zone System speed, not a speed determined according to ISO criteria.

No, determined by ring-arounds and printing. Developer was Acutol. There is no way Acros is 100.

 

[ic-racer]

For most purposes, the CI wouldn't matter in a practical test of speed using delta-x criteria.

 

[Andrew O'Neill]

No, determined by ring-arounds and printing. Developer was Acutol. There is no way Acros is 100.

For you. For someone else, it may be different. Why must you always think "my way or the highway"? ISO's/EI's are personal.

 

[John Wiegerink]

No, determined by ring-arounds and printing. Developer was Acutol. There is no way Acros is 100.

I get a solid speed of 320 with Acros, according to ISO criteria! I've said this at least ten times on the site that no meters are exactly the same, nobody meters exactly alike, not people point there meter in the exact same spot................! I haven't even mentioned camera variance or different developing techniques etc.. Your EI 80 is my EI 125 or my EI125 is your EI 80, da, da, da.

 

[Milpool]

No, determined by ring-arounds and printing. Developer was Acutol. There is no way Acros is 100.

Printing is the best way to determine the EI you prefer to use, but the ISO speed is 100. Foma films seem to be the exception as the data sheets for those films indicate the nominal speeds on the box are really EIs, not ISO speeds.

Maybe Acros doesn’t quite reach full emulsion speed in Acutol.

 

[Milpool]

Agree. It moves relatively little versus a simple fixed density criterion.

For most purposes, the CI wouldn't matter in a practical test of speed using delta-x criteria.

 

[Stephen Benskin]

Found an Acros test.

Xtol 1:1, Jobo, Mark VI calibrated sensitometer

Acros, CI 0.61, 90

 

[Craig]

In my experience I find Delta 100 and Acros develop full speed.

 

[Keith Tapscott.]

I can't give a definitive answer to the OP except that I find that I prefer enlarging negatives that have been exposed a bit more generously than the ISO rating printed on the film box. As for development, that depends on the light source of the enlarger etc.

 

[Augustus Caesar]

Printing is the best way to determine the EI you prefer to use, but the ISO speed is 100. Foma films seem to be the exception as the data sheets for those films indicate the nominal speeds on the box are really EIs, not ISO speeds.

Maybe Acros doesn’t quite reach full emulsion speed in Acutol.

That's what I did. I printed the negatives. Acros is about 50, no more. T-Max is 100, Delta 100 is about 80.

 

[Augustus Caesar]

I get a solid speed of 320 with Acros, according to ISO criteria! I've said this at least ten times on the site that no meters are exactly the same, nobody meters exactly alike, not people point there meter in the exact same spot................! I haven't even mentioned camera variance or different developing techniques etc.. Your EI 80 is my EI 125 or my EI125 is your EI 80, da, da, da.

I tested a bunch of films under the same conditions. T-Max 400, Tri-X, HP5+, and Neopan 400 all measure out at 250. T-Max 3200 is about 800. Delta 3200 is about 1000. Pan-F is about 25. FP4 is about 100. Acros is about 50. Tested in FX-39 and Acutol.

 

[MattKing]

That's what I did. I printed the negatives. Acros is about 50, no more. T-Max is 100, Delta 100 is about 80.

For you.

 

[John Wiegerink]

I tested a bunch of films under the same conditions. T-Max 400, Tri-X, HP5+, and Neopan 400 all measure out at 250. T-Max 3200 is about 800. Delta 3200 is about 1000. Pan-F is about 25. FP4 is about 100. Acros is about 50. Tested in FX-39 and Acutol.

Your Acros speed of 50 is way, way off. I get a speed of 320 with Acros.........! If you're not getting an EI of 320 with Acros in Acutol or FX-39II you are doing something drastically wrong. See, not everybody's film speed EI is the same even with all the same equipment and developer. It's like cooking...........my T-bone steak doesn't taste like the one you made and they even came from the same steer. That's no BULL.

 

[Augustus Caesar]

For you.

It seems this corresponds to the results that others get.

 

[Andrew O'Neill]

It seems this corresponds to the results that others get.

Yes, your findings will jive with some people, but not EVERYONE.

 

[Craig]

I tested a bunch of films under the same conditions. T-Max 400, Tri-X, HP5+, and Neopan 400 all measure out at 250. T-Max 3200 is about 800. Delta 3200 is about 1000. Pan-F is about 25. FP4 is about 100. Acros is about 50. Tested in FX-39 and Acutol.

Sounds like you're underdeveloping if you can't get box speed out of anything. FX-39 is supposed to be a full speed developer, unlike Perceptol for example.

 

[John Wiegerink]

It seems this corresponds to the results that others get.

Yes, your speed for Acros is just fine for you, but not for me. Now Ed next door says your Acros speed is the exact same as his. A lot of folks will match your speeds and a lot of folks won't. Just the way it is.

 

[mshchem]

220, 221 whatever it takes

 

[DREW WILEY]

John - It seems like it's either your meter itself, or else your style of metering, which is WAY OFF. Meters are in fact factory calibrated to distinct critical standards, and not just willy nilly. Of course, for your own closed-loop personal purposes, you can assign any values you wish; but for those of us using properly calibrated meters - Acros at 320? - downright ridiculous.

But I don't buy into any of this "matched speedpoint" doctrine anyway. Why bother? Different films and their respective film curves have different personalities. Some are indeed similar to certain others. But you can't beat all of them into submission.

 

[John Wiegerink]

John - It seems like it's either your meter itself, or else your style of metering, which is WAY OFF. Meters are in fact factory calibrated to distinct critical standards, and not just willy nilly. Of course, for your own closed-loop personal purposes, you can assign any values you wish; but for those of us using properly calibrated meters - Acros at 320? - downright ridiculous.

But I don't buy into any of this "matched speedpoint" doctrine anyway. Why bother? Different films and their respective film curves have different personalities. Some are indeed similar to certain others. But you can't beat all of them into submission.

Drew,
My comments on this discussion are all "tongue in cheek". I was trying to get the point across that my EI iis right for me and Mr. Caesar's EI right for him. Yes, an EI 0f 320 for Acros is dreaming for sure. Some folks think that if you're not rating your film exactly like they are, you don't know what you are doing. Film, equipment, and technique are different for most of us here. Most important is where you point your meter and how you judge the scene.

 

[Milpool]

I wonder if this might have something to do with the much higher highlight contrast Acros has. If you have a subject with a wider than normal luminance range Acros will tend to have a higher total density range than the other two films, and it could be as you adjust for this when printing it is pushing your shadows down.

On the other hand, that would conflict with the results you’re getting with the high speed films because there again TMY-2 (like Acros) tends to develop to higher highlight densities than say HP5, and yet you are finding those two films have the same EI for you.

The only thing I can come up with is perhaps there is something Acros uniquely doesn’t like about that developer. I mean those crawley/FX things are silly anyway.

That's what I did. I printed the negatives. Acros is about 50, no more. T-Max is 100, Delta 100 is about 80.

 

[DREW WILEY]

Thanks for clarifying that, John. I don't pay much attention to "Emojis".

Milpool - what makes you think Acros has higher highlight contrast? It can't even be "plus" developed to the same gamma level as some similar speed films. If there's a film among that class which has something of an upswept highlight curve, it's Delta 100, though nowhere to the same degree as old Plus X pan sheet film.

 

[Keith Tapscott.]

Sounds like you're underdeveloping if you can't get box speed out of anything. FX-39 is supposed to be a full speed developer, unlike Perceptol for example.

It could be due to the type of enlarger light source and the desired contrast required for personal use.
If I recall correctly, the standard development time that Kodak suggests gives a contrast index of around C.I. 0.56-0.58 which should be suitable for most modern enlargers designed for either colour papers or variable contrast papers. Kodak used to suggest C.I.0.45 for condenser enlargers.
Grade 2 papers were considered to be the usual normal grade.
Users of 35mm films often developed their films for grade 3 papers as their normal grade, so would use an even shorter development time.
As you pointed out, this could require lower ISO/ASA meter settings.

 

[ic-racer]

I have seen negative or derogatory comments about forum participants’ personal film speeds and/or contrast index (including my own) in just about every thread on the subject.

 

[John Wiegerink]

I would never say someone's own personal film speed is wrong as long as it was within the ballpark of normal. My saying that I get an EI of 320 for Acros is not normal as Drew pointed out. Different strokes for different folks!