Dynamic Range & Film ISO

drp · Jun 9, 2021

Hello,

Is it correct to assume that lower ISO film such as Kodak T-Max 100 will have more dynamic range or better tonality than T-Max 400? And the same can be said of color negative and slide film?

Thanks!

Ko.Fe. · Jun 9, 2021

Difference is next to none. The only visible difference I see is then ISO 400 film is pushed @3200 and higher under low light.

Paul Howell · Jun 9, 2021

In my experience Tmax 100 has a steeper Characteristic curve than Tmax 400, meaning higher contrast, the difference is not as great as between other traditionally grain films in the same family, but you do get a tad more range with Tmax400, in terms of tones, personal preference. I generally shoot Tmax 400 as I think it is more versatile as a travel film, while Tmax 100 has small grain and very high resolution, for detail it cannot beat other than a microfiche film. For a complete look google Kodak data sheets for both.

MattKing · Jun 9, 2021

All else being equal, the only practical difference results from differences in grain. Visible grain affects the subjective appearance of the various tones, so "tonality" that is pleasing in a low ISO film may not be as pleasing in a high ISO film.
Conversely, increased grain can lead to higher perceived "sharpness".
So much of this is both objective and subjective.
The other thing to be aware of is that T-Max 100 and T-Max 400 aren't designed to give the exact same shape of characteristic curve. As a result, the "tonality" will be different no matter what contrast you develop to.

Craig75 · Jun 9, 2021

Slower the film the smaller the dynamic range.

Lachlan Young · Jun 9, 2021

Old Gregg said:
"Film Developing Cookbook" by Anchell and Troop states repeatedly that faster films have greater dynamic range because they feature wider variety of crystal sizes in their emulsions, IIRC. It is visible in their datasheets: the characteristic curves tend to be longer.

Not really the case (if it even ever was in the era of uncontrolled polydisperse emulsions). You can effectively engineer a negative working emulsion to whatever latitude you want today. Most emulsions are engineered to meet the needs of their target markets - not some generic catch-all.

MattKing · Jun 9, 2021

Lachlan Young said:
Most emulsions are engineered to meet the needs of their target markets

+1
Higher speed films tend to be designed with longer characteristic curves, because they tend to be used in circumstances that benefit from longer characteristic curves.
But you could have a low speed, long characteristic curve film, if you thought there was a market for it.

radiant · Jun 9, 2021

I think more interesting question is how much really and does it make any bloody difference?

IMHO saying something is "smaller" or "larger" without quantity and relativity is just waste of bits ..

gone · Jun 9, 2021

You may be able to make that assumption w/ the film you mentioned, but in my experience, film speed has nothing to do w/ exposure latitude. Some films got it, and some don't, irrespective of their ISO. I can shoot 400 ISO Tri-X at all kinds of different exposures, develop it normally, and get good negs. If I tried that w/ something like Foma 400 (which is a good film that I regularly shoot). good luck! Every film will have it's own DNA, and that will determine exposure latitude.

ic-racer · Jun 9, 2021

dede95064 said:
Hello,

Is it correct to assume that lower ISO film such as Kodak T-Max 100 will have more dynamic range or better tonality than T-Max 400? And the same can be said of color negative and slide film?

Thanks!

No.

Lachlan Young · Jun 9, 2021

MattKing said:
But you could have a low speed, long characteristic curve film, if you thought there was a market for it.

You've started the countdown timer on the Panatomic-X obsessives bursting out of the woodwork... Not that it had (or has) any advantage over current 100 speed high-aspect ratio grain/ controlled crystal growth emulsions.

Alan Edward Klein · Jun 9, 2021

Tmax 100 and 400 do show a difference on my scans of 4x5. You can especially see it in the sky area. Whether it matters to you, is up to you. Scanned with an Epson V850.
Tmax 100 4x5 Barn #1 | Chamonix 45H-1, Schneider Symmar APO 150mm, yellow… | Flickr
Tmax 400 4x5 Fence | Chamonix 45H-1, 90mm with center filter, Tmax 400, E… | Flickr

Tmax 400 in 35mm (sorry I don't have Tmax 100 in 35mm) Removing ground brush with fire - 35mm Tmax 400 | Flickr

takilmaboxer · Jun 10, 2021

dede95064 said:
Hello,

Is it correct to assume that lower ISO film such as Kodak T-Max 100 will have more dynamic range or better tonality than T-Max 400? And the same can be said of color negative and slide film?

Thanks!

No, it is not. And you're unlikely to get the truth on this forum, just a wide variety of opinions.

Bill Burk · Jun 10, 2021

Looks like both 100 and 400 have about 10 stops from the speed point before they start to shoulder. Normal scenes are considered to average about 7 stops.

In practical terms they both allow for an average scene to be exposed with latitude towards overexposure by two stops.

That doesn’t count one or two stops under exposure where people get away with less quality but enjoy the results.

Dynamic Range & Film ISO

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