Increasing dynamic range of film scan through HDR techniques

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drjoke

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Some niche photographers have discovered the secret of applying HDR techniques to increase dynamic range of film. However, they would not like to reveal their secret.

Here is what I gather.

1) They use film scanner to scan their negatives with analog gain of -10, 0, and +10.

2) They combine the resulting JPGs with HDR programs

It sounds very simple. I tried something like this last year, but got a lot of ghosting and artifacts. I heard that HDR programs have improved quite a lot, so I might try this again.

Yet, I wonder if these HDR programs are better than Vuescan or Silverfast at combining pictures of analog gain. It would really excite me because, either I am not doing it right, but I am trying hard to see significant gain in dynamic range with film scanning programs.
 
The "Convert to HDR" feature in Photoshop CS3 has been greatly improved from CS2, and includes an auto-align feature which matches the multiple exposures (and thereby eliminates ghosting).
 
Dear anyone with experience, are these HDR programs including Photoshop better than Vuescan or Silverfast at this?
 
drjoke said:
Some niche photographers have discovered the secret of applying HDR techniques to increase dynamic range of film. However, they would not like to reveal their secret.
Click to expand...

From a single frame of film this is very unlikely to really achieve anything that couldn't be done with a single pass scan. The brightness range of the original scene has already been mapped into the exposure range of the film so not much to do there.

Depending on the scanner and emulsion, slides might benefit a little but only due to the higher density. Negative films only have a density range of around 2.0 so for film scanners like the Nikons this is typically a non-issue. Scanning with a +10 and -10 gain then combining is not going to extract more information that isn't there to begin with.
 
craygc said:
From a single frame of film this is very unlikely to really achieve anything that couldn't be done with a single pass scan. The brightness range of the original scene has already been mapped into the exposure range of the film so not much to do there.

Depending on the scanner and emulsion, slides might benefit a little but only due to the higher density. Negative films only have a density range of around 2.0 so for film scanners like the Nikons this is typically a non-issue. Scanning with a +10 and -10 gain then combining is not going to extract more information that isn't there to begin with.
Click to expand...


True. Using HDR techniques on a scan is not going to increase the range captured by the actual negative.

But there are times when the DR of the negative exceeds what a scanner can capture in one pass. You are left with the choice of blowing the highlights or crushing the shadows.

But doing a wedge of multiple scan passes and combining them can get around this problem. I've done it with my Nikon 9000ED and it works quite well, although a lot depends on the accuracy and repeatability of the film advance. None of the these scanners are pin registered. I believe Silverfast gets around this problem, by making three exposures of every scanline pass, during a single scan.
 
Harry Lime said:
But there are times when the DR of the negative exceeds what a scanner can capture in one pass. You are left with the choice of blowing the highlights or crushing the shadows.
Click to expand...

With negative film, and scanners such as the Nikons, that should really happen if the scanner exposure is set correctly. As I mention above, the density range of negs is in the vicinity of 2.0 and that is an easy walk for these scanners.
 
Working with Negitives in HDR in Lightroom/PS

Working with Negitives in HDR in Lightroom/PS

Hello guys. This is my first post here.

Harry Lime said:
I believe Silverfast gets around this problem, by making three exposures of every scanline pass, during a single scan.
Click to expand...

I'm new to silverfast and started scanning my Tri-X negs in HDR 16bit mode to capture the highest dynamic range for editing in Lightroom. Since this captures the file in negative, and there (seems to be) no simple "convert to positive" button in Lightroom, All I've read online is to manually invert the linear tone curve, and set up a preset to do this instantly. The issue arises that all of the control sliders and graphs work inverted now.

Is there ANY reason why I wouldn't set up an action in photoshop to do a simple "command-I" where it inverts the file, then resaves the image as a positive and work in lightroom with that file?

Thanks for your reply,
Will
 
I have had encouraging results with Lightroom and the plugin LR/Enfuse. So far, I have worked with a single TIFF file and multiple virtual copies in Lightroom. I "bracket" the EV values in Lightroom and Enfuse merges them togehter. When I have the blended image, I delete the virtual copies. This also works for digital files that weren't bracketed in the camera. Lightrooms graduated neutral density filters work nicely to tame wide dynamic range as well. NO TONE MAPPING! Not HDR. Thank goodness.
I will try multiple scans of the same negative soon.
 
venchka said:
I have had encouraging results with Lightroom and the plugin LR/Enfuse. So far, I have worked with a single TIFF file and multiple virtual copies in Lightroom. I "bracket" the EV values in Lightroom and Enfuse merges them togehter. When I have the blended image, I delete the virtual copies. This also works for digital files that weren't bracketed in the camera. Lightrooms graduated neutral density filters work nicely to tame wide dynamic range as well. NO TONE MAPPING! Not HDR. Thank goodness.
I will try multiple scans of the same negative soon.
Click to expand...

Since I'm using Silverfast (and Epson v600 scanner) I set it to scan HDR. Why not just work with the .Tif file from there inside lightroom? It's my understanding that it's scanning at the full dynamic range already, so you don't have to work on 3 separate files. Am I wrong?

p.s. my photos can be found here: http://www.willstarphotography.com/blog
and
http://www.flickr.com/wkstar

Only the latest ones have been scanned using silverfast.
 
I used to scan negative film in multiple passes with a Coolscan, because it was clipping highlights and shadows. In order to capture all of the latitude of the negative, I often needed three or four passes at different analog gains, which I combined into an HDR master file.

Now, I scan my negatives as positives (slides), which allows me to catch 100% of the negative's latitude in one pass. Then I can control contrast and color from there. So HDR is really not necessary.

Here's an example scan with this workflow:
 
You may use 16 bit Tiff files, because jpeg are too compressed.
I think you can choice this option before scanning, can't you?
 
I don't use Silverfast nor do I own a V series scanner. I do need to try scanning B&W negatives as positives & inverting. I did that with my old scanner & the results were good.
Yes. I scan 16 bit greyscale TIFF files with EpsonScan.
 
I agree that JPEG probably shouldn't be used as a scanning format, but only because storage is cheap these days... Quality-wise, I've done the comparison of scanning into a 16 bit TIFF and an 8 bit JPEG, and because of film grain at 4000 DPI, there is virtually no difference.

Either way, it's unrelated to the issue of HDR and getting the most information out of the negative. I consider it a bug of the Coolscan series that it introduces so much artificial contrast when scanning negatives. Since it works fine to scan as a positive, the scanner is obviously capable of capturing a wider contrast range, but Nikon decided for some reason to make it impossible to access in negative mode.
 
gekopaca said:
OK… but HDR apps work better with TIFF files, because there's more informations in.
Click to expand...
It depends on what you mean by "information"—the errors introduced by JPEG compression are generally far smaller than the errors (noise) introduced by the scanner. So another way of looking at it is that the TIFF preserves your scanner's noise better than the JPEG.
 
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