Acros Dynamic Range

[Adam Kavalunas]

Hi guys,

I've tried searching here, and on the web but couldn't find what I was looking for. Maybe i'm not a good searcher....:) Simple question: What's the DR for Acros? I typically just shoot Astia and then do a B&W conversion if I feel like the image might be a good candidate for B&W. But I recently bought a box of Acros and will actually be shooting scenes directly in B&W so I would like to know how much range I can expect to be able to capture. Thanks!

Adam Kavalunas
www.plateauvisions.com

[Kirk Keyes]

It's linear for a long way out past a normal exposure range.

Tell me how you determine DR and I'll see if I can get you a number from my tests with it.

[Adam Kavalunas]

Well, I usually can get about 4.5-5 stops from Astia. Meaning if I meter a scene and the brightest and darkest spots are roughly 5 stops apart, usually I can get detail in those sections without the highlights blowing out or shadows becoming black.

[Joanna Carter]

Using the Zone System, I got somewhere near 14 stops of range on this shot:

http://grandes-images.com/en/Heritage_%26_Restoration_files/Media/OakworthStationMastersOffice/OakworthStationMastersOffice.jpg

The highlights were the sky and the mantle on the gas lamp, the shadows are between the bottom of the desk and the chimney breast. There is s lot more detail in the original neg than can be put into a small web image.

[Robert Hughes]

Most impressive!

[Leigh]

Using the Zone System, I got somewhere near 14 stops of range on this shot
That's very nice, Joanna.

I suspect 4x5. Developer/time?

Thanks.

- Leigh

[Kirk Keyes]

As Joanna shows above, you've got a lot of exposure range with Acros to play with. Especially if you're used to shooting transparancies!

Jump in and get some Acros - it's a great film.

[Adam Kavalunas]

Wow 14 stops! From what I've gathered so far, most people are saying about 10 stops. Even at 10 thats double what I'm used to. Any other opinions out there? C'mon, I'm sure most of you have shot this film before. Thanks!

[Joanna Carter]

Wow 14 stops! From what I've gathered so far, most people are saying about 10 stops. Even at 10 thats double what I'm used to.
Certainly, 10-11 stops would be expected from most B&W films, not just Acros. Using the Zone System allows you to extend that and, at the othert end of the scale, it is possible to increase the contrast of a very flat 3-4 stop range shot to something more punchy.

[Joanna Carter]

That's very nice, Joanna.

I suspect 4x5. Developer/time?
Yes, definitely 4x5. The developer would have been Ilford DD-X, diluted 1+9 instead of the regular 1+4 @ 24°C for around 7 mins in a Jobo ATL1500, if I remember rightly.

[Leigh]

The developer would have been Ilford DD-X, diluted 1+9 instead of the regular 1+4 @ 24°C for around 7 mins in a Jobo ATL1500, if I remember rightly.
Interesting dilution and time. I'll try it.

I've been using DD-X 1+4 for 10 mins @ 20°C in a tank with manual agitation.

Thanks very much.

- Leigh

[Adam Kavalunas]

So apparently, the developing of the film has something to do with the resulting DR? Sorry, please excuse my novice questions, but this is all pretty foreign to me. What would I expect from a lab, since I won't be developing this myself?

[Leigh]

So apparently, the developing of the film has something to do with the resulting DR? Sorry, please excuse my novice questions, but this is all pretty foreign to me. What would I expect from a lab, since I won't be developing this myself?
Read up on the Zone System. In particular read the book The Negative by Ansel Adams.

Resolving subject DR onto a negative correctly requires considerable experimentation and good process control on your part.

The chemistry will be consistent, but you must decide what you want.

With proper choice of exposure and development you can capture a wide gamut of subject ranges quite effectively.

Most labs that do 4x5 will develop to your specifications.


- Leigh

[Joanna Carter]

Interesting dilution and time. I'll try it.

I've been using DD-X 1+4 for 10 mins @ 20°C in a tank with manual agitation.
It took quite some searching to find the best time and temperature for Acros in DD-X; the best I found for 1+4 @ 20°C was 8:30 for standard contrast.

I just looked up the chart for the shot I showed; it was actually 5:30. The standard development for 1+9 @ 24°C should be 7:30.

[Leigh]

the best I found for 1+4 @ 20°C was 8:30 for standard contrast.
That's what I would expect for rotary tube processing; about 15% shorter than for tank.

I'm curious about your elevated developing temperature (24°C v. 20°C). Is that just to reduce processing time?

Thanks.

- Leigh

[Oren Grad]

So apparently, the developing of the film has something to do with the resulting DR? Sorry, please excuse my novice questions, but this is all pretty foreign to me. What would I expect from a lab, since I won't be developing this myself?

Within a pretty broad range, the developing of the film doesn't have too much to do with the SBR that the film can record. What it does affect, critically, is how easy it will be to get the information from the negative into a print, especially if you are printing in the darkroom; there's more leeway with scanning.

More specifically, if you're printing on a particular silver paper, you need to have a negative whose overall density range doesn't exceed the exposure scale of your paper. Otherwise, you'll need dodging, burning and/or masking to get the dense highlights into your print without losing shadow detail.

[Adam Kavalunas]

Thanks Oren,

I'll be scanning these negs, and printing most likely with a Lightjet. I have yet to determine which paper I will use though. Basically I just want to make sure that the DR of the scene fits on the DR of the film, and after scanning, I can make any adjustments to contrast that I want.

[Filmnut]

I've shot quite a bit of Acros, and like it very much, usually I process in Kodak Xtol, or Rodinal, but it will work nicely in most developers.
By all means do some research on the different ways to process B&W film, but at some point you just have to jump in and start to shoot, and evaluate your work from there. So, I'd suggest you go out and shoot "normal" use a developer that you can get readily, and then when you learn what that can, and cannot do, then get into the processing/exposure variations.
Keith

[Oren Grad]

I'll be scanning these negs, and printing most likely with a Lightjet. I have yet to determine which paper I will use though. Basically I just want to make sure that the DR of the scene fits on the DR of the film, and after scanning, I can make any adjustments to contrast that I want.

OK. So what you need to do is make a few exposures of a scene that's representative of the maximum brightness range you think you'll want to record, have the lab develop them, and see how your scanning goes. If the negatives easily yield a full-information scan, you're all set. If not, then you'll need to start thinking about getting your lab to pull the development, or using HDR scanning approaches to capture the full density range.

For a reasonably-developed negative, usually you shouldn't need scanning heroics. FWIW, although I do almost all of my own B&W developing, on the rare occasions over the years when I've gone with a commercial lab for one reason or another, I've almost always found that the negatives come back developed to a much higher contrast than I prefer. The only way to know where you stand will be to do a test run with your lab and see what you get.

[ic-racer]

Questions like this can be a little difficult to answer because the 'standard' 21-step wedge, of course, only shows 10.5 stops. And even in that case the exposure needs to be perfectly centered to show the 10.5 stops.

[I Am Luna]

Using the Zone System, I got somewhere near 14 stops of range on this shot...
Amazing!

[jvuokko]

Questions like this can be a little difficult to answer because the 'standard' 21-step wedge, of course, only shows 10.5 stops. And even in that case the exposure needs to be perfectly centered to show the 10.5 stops.

4x5 wedge with 0.6 or 0.9 ND filter over it will give a much wider range.. If precise testing is required.

However I guess that most will use just estimations of shoulder part for low contrast developments. Simply by extending curve or calculating CI value from the partial curve.


I like the Acros film. However, it's not linear film in my process. It has a little more S shape than Hp5+ (which is pretty linear).
But things varies depending on developer and developing style.

[Steve Gledhill]

A late response from me in this thread - I've been away ...

I posted this a while ago (http://www.largeformatphotography.info/forum/showthread.php?t=55797&highlight=stop). I'm not reposting to try a comparison or competition with Acros but simply to confirm the potentially huge SBR available from some of our films - in my case at least 18 stops with my workflow and my chosen film. Clearly it depends to a significant extent on how you plan to print from the negative but some simple experimentation is a great way to explore the limits.

[Drew Wiley]

Extreme contractions come with the penalty of reduced micro-contrast and lower film speed; so the rules of the game should be a little more clearly defined. ACROS has
plenty of wiggle room, but not as much as some films with more of a true straight line
characteristic. Where it really excels is at very long exposures.