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05-05-2019, 07:22 PM   #46
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QuoteOriginally posted by nickthetasmaniac Quote
I know you’re talking about EL, not DR, and that’s what I’m skeptical of. I don’t believe you can over or underexpose Delta3200 to the same degree as FP4 (for example) and still retain a usuable image. Do you have a reference that demonstrates high ISO films have better EL?
Other than 47 years of experience having shot everything under the sun including many extinct films like 3M/Scotch 640T or Kodak TechPan, I'd say check out many of @LesDMess posts of his exposure latitude tests and it becomes apparent. Delta and TMax don't quite have the same EL as their other equivalent EI rated emulsions, but even Delta 3200 developed in a standard process using DDX will have a significantly higher EL than FP4+ developed in ID11 at it's rated EI.

Here from Ilford's own data sheet states that FP4+ can be shot at E.I. 50 thru E.I. 200. Of course, we're talking exposure latitude and not how much the film can be push or pull processed, but they are related. That gives FP4+ about +1.3 EV to about -.6EV recommended latitude.
https://www.ilfordphoto.com/amfile/file/download/file/1919/product/686/

With Delta 3200, Ilford's tech data sheets state EI from 400 thru 25,000, although for 'best results' they suggest EI 400-3200. So even with the more conservative numbers, it's +3EV vs. the FP4+ at a range of 2EV for nominal exposures.
https://www.ilfordphoto.com/amfile/file/download/file/1913/product/682/

I would expect that even with the worst matched developers, a higher ISO emulsion will still have a significantly higher exposure latitude than a lower ISO film.

05-05-2019, 10:57 PM   #47
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I think it's because the higher speed films are made lower contrast to compensate for the increased contrast from longer development?
05-06-2019, 07:39 AM - 2 Likes   #48
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QuoteOriginally posted by Alex645 Quote
Other than 47 years of experience having shot everything under the sun including many extinct films like 3M/Scotch 640T or Kodak TechPan, I'd say check out many of @LesDMess posts of his exposure latitude tests and it becomes apparent. Delta and TMax don't quite have the same EL as their other equivalent EI rated emulsions, but even Delta 3200 developed in a standard process using DDX will have a significantly higher EL than FP4+ developed in ID11 at it's rated EI.

Here from Ilford's own data sheet states that FP4+ can be shot at E.I. 50 thru E.I. 200. Of course, we're talking exposure latitude and not how much the film can be push or pull processed, but they are related. That gives FP4+ about +1.3 EV to about -.6EV recommended latitude.
https://www.ilfordphoto.com/amfile/file/download/file/1919/product/686/

With Delta 3200, Ilford's tech data sheets state EI from 400 thru 25,000, although for 'best results' they suggest EI 400-3200. So even with the more conservative numbers, it's +3EV vs. the FP4+ at a range of 2EV for nominal exposures.
https://www.ilfordphoto.com/amfile/file/download/file/1913/product/682/

I would expect that even with the worst matched developers, a higher ISO emulsion will still have a significantly higher exposure latitude than a lower ISO film.
Interesting!

The strong nonlinearity of the characteristic curve of Delta 3200 suggests that the emulsion includes some grains that are very sensitive light as well as some grains that are less sensitive to light.

If i had to guess, the difference between FP4+ and Delta 3200 isn't just the grain size (Delta 3200 would have much larger grains to make it more sensitive) but also the variation in grain size. If FP4+ has small grains of uniform size, it would contribute to creating silky-smooth images. If the emulsion of Delta 3200 includes grains of a range of sizes, then it would have both a very wide latitude and a very wide range of possible EI.
05-06-2019, 09:05 AM   #49
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QuoteOriginally posted by photoptimist Quote

If i had to guess, the difference between FP4+ and Delta 3200 isn't just the grain size (Delta 3200 would have much larger grains to make it more sensitive) but also the variation in grain size.
Yes, for sure. I only cited those two specific emulsions because @nickthetasmaniac was using them as an example, but ISO isn't the only factor that would affect DR or EL. Just comparing Ilford's own 400 rated HP5+, Delta, and XP2 shows that ISO isn't the only factor.

06-20-2019, 10:36 AM - 2 Likes   #50
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Hi, Iím the guy who posted that video on YouTube

Hi, Iím the guy who posted thatvideo on YouTube. Thanks for all who watched it. And thanks for thisdiscussion. I learned a lot reading this thread.

I read through this forum post andfigured I should answer a few of the questions.

Isnít this a Latitude test, not a DynamicRange test? That is correct. Latitude would be a better title for the video.But the intended audience leans toward digital, and ďDynamic RangeĒ is a termthey understand and would type into a Google search.

Why B&W? Because I donít knowhow to develop color yet.

A bunch of you pointed out that otherfilms have better dynamic range or latitude. Thanks for telling me! I need to knowthat kind of stuff.

Why TMax? Because thatís what Ibought when I went film shopping.

Why 100 ISO? Because I wanted to match the ISO on thedigital camera. Why ISO 100 on the digital camera? Because thatís the nativeISO so it will yield the best results.

Why develop in D76? Because according to my Google search, that isa good overall middle-of-the-road developer for most shooting styles.

In case you are curious about me. Itook a ďHow to Develop FilmĒ course at my local community college. Then I wentout and made this video. Iíve been an avid photographer for a few decades. Exclusivelydigital for the past 15 or 20 years. Before that, I just dropped my film off atthe store for processing.
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