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Is there any benefit from pushing or pulling film development for scanning
Aug 13, 2021 09:21:15   #
selmslie Loc: Fernandina Beach, FL, USA
 
You can expose film base at an ISO that is different (within reason) from the box speed but you will need to adjust development time or development concentration.

To show this effect I used Ilford FP4 (ISO 125) and HP5 (ISO 400) and found development that would produce similar characteristic curves to my control - FP4 at ISO 125 developed in Xtol 1+2 for 7:00 @ 75°F.

To pull about one stop I exposed FP4 at ISO 50 and developed it in Xtol 1+3 for 7:40 @ 75°F. I pushed HP5 to ISO 800 and developed it in Xtol 1+1 for 12:30. I used these two films because I had plenty of them on hand but the results will be similar for others.

The adjusted times and concentrations were based on an earlier test that resulted in this set of characteristic curves:



As you can see, the two FP4 curves are quite close together over most of their range. But the HP5 curve, although it produced about the same overall contrast from EC-5 to EC+6, has a slightly different shape. The following side by side comparisons show whether this can make a difference. Each image pair has HP5 on the left and FP4 on the right.

The following pairs were taken using two backs on the Hasselblad. Each HP5 exposure was calculated for ISO 800. Since the FP4 was exposed at ISO 50 it got 4x as much exposure.

The results showed that pushing did not provide any benefit for HP5 but it might not work well for the shadows.

For FP4 it doesn't make much difference. Pulling just calls for more exposure and less development.
The rendition is almost the same
The rendition is almost the same...
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The expected difference in grain between FP4 and HP5 is typical
The expected difference in grain between FP4 and H...
(Download)
But the difference is clearer when the scene has a wide dynamic range
But the difference is clearer when the scene has a...
(Download)

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Aug 13, 2021 10:07:43   #
selmslie Loc: Fernandina Beach, FL, USA
 
Just fixed a typo. HP5 is on the left, FP4 on the right.

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Aug 14, 2021 11:29:12   #
jackm1943 Loc: Omaha, Nebraska
 
Interesting. When I decided that I would be scanning rather than printing, I maintained normal exposure but used between N-1 and N-2 development to try to reduce the negative's contrast. I did no testing nor do I have any data to determine if they scanned better but they "appeared" to scan better. Many of my old negs are pretty contrasty and do not scan well, getting way too much grain in the dense parts of the neg. However, with Photoshop, sky replacement, photographing negs rather than scanning them, etc., it is now fairly easy to correct that. For what it's worth, I used TMX film and TMax developer during the last few years I shot b/w.

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Aug 14, 2021 11:52:09   #
selmslie Loc: Fernandina Beach, FL, USA
 
jackm1943 wrote:
Interesting. When I decided that I would be scanning rather than printing, I maintained normal exposure but used between N-1 and N-2 development to try to reduce the negative's contrast. I did no testing nor do I have any data to determine if they scanned better but they "appeared" to scan better. ...

Some scanners have trouble with dense negatives so minus development is a common way to address that. It reduces the range of film densities.

I often have trouble with the Coolscan and scenes with too much dynamic range (DR). The Coolscan can read a little more density than the Epson but the Epson makes it easier to deal with a wider DR. Adding some exposure can help with the shadows and it does not add contrast.

Using as much of the scanner's DR range as you can makes it easier to get a full range of values.

In A Practical Guide to Film Characteristic Curves – Part 3 I covered this topic with a little more detail.

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Aug 14, 2021 12:53:39   #
jackm1943 Loc: Omaha, Nebraska
 
selmslie wrote:
Some scanners have trouble with dense negatives so minus development is a common way to address that. It reduces the range of film densities.

I often have trouble with the Coolscan and scenes with too much dynamic range (DR). The Coolscan can read a little more density than the Epson but the Epson makes it easier to deal with a wider DR. Adding some exposure can help with the shadows and it does not add contrast.

Using as much of the scanner's DR range as you can makes it easier to get a full range of values.

In A Practical Guide to Film Characteristic Curves – Part 3 I covered this topic with a little more detail.
Some scanners have trouble with dense negatives so... (show quote)


My scanner, an old Epson 2450, did a pretty good job on 4x5 when wet scanning, fair on 120 and useless for 35mm using VueScan software. I was considering getting a better scanner but recently found that it is much easier to just photograph the negs. The photographed images are better but that could just be due to the limitations of my old scanner. Since I'm no longer shooting film I'll just continue to photograph my old negs, some over 30 years old.

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Aug 14, 2021 16:33:50   #
selmslie Loc: Fernandina Beach, FL, USA
 
jackm1943 wrote:
My scanner, an old Epson 2450, did a pretty good job on 4x5 when wet scanning, fair on 120 and useless for 35mm using VueScan software. I was considering getting a better scanner but recently found that it is much easier to just photograph the negs. The photographed images are better but that could just be due to the limitations of my old scanner. Since I'm no longer shooting film I'll just continue to photograph my old negs, some over 30 years old.

My flatbed Epson V750 at its optical resolution limit of about 2400 ppi produces a digital scan of under 8MP for the 24x36mm format. My Coolscan 9000 at 4000 ppi produces over 21MP. Taking a raw macro image of the film can do better than either scanner when it comes to resolution.

Scanning is best for lots of images taken on film before the digital age or for medium or large format film. I have scanned over 35,000 images. I would not have done that with a camera.

If you cut out the middle man (film) any 24MP digital camera might be better than a scanned image in most cases.

But there is still an advantage to film, even if our objective is to scan a 35mm image. It has a wider dynamic range. We can see that in the initial graph. Film can reach 6 stops (probably more) above middle gray while digital reaches only about 3 stops.

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