Scan + HDR

[DavidStone]

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Now that I have the HDR software form Nik, I'm thinking of re-scanning some of my long-scale "difficult" BW negatives to discover if HDR can produce a better result (i.e. print) than a single scan. I have the Epson V700 scanner, and I'm using Vuescan. I also have Epson Scan that came with the scanner, although I've not used it much.

 

But - I can't discover a way of producing two or more scans of different exposures from one neg. I feel that it must be possible, and that I'm missing somethng obvious.

 

Has anyone tried this? Can anyone offer any advice from their own experience?

 

David

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Without knowing your actual hardware or software I can offer the hint that you have to disable automatic exposure correction when scanning for HDR. You then can set the contrast setting to low and the brightness setting to dark, medium and bright, respective, for three consecutive scans.

 

On the other hand, you might want to set the resulting file format to something like TIFF with a bit depth of more than 8. Bit depths of 12 and 16 are common values. In that case, you need but one scan which you then can process with the tone mapping part of the HDR procedure.

[DavidStone]

Without knowing your actual hardware or software I can offer the hint that you have to disable automatic exposure correction when scanning for HDR. You then can set the contrast setting to low and the brightness setting to dark, medium and bright, respective, for three consecutive scans.

 

On the other hand, you might want to set the resulting file format to something like TIFF with a bit depth of more than 8. Bit depths of 12 and 16 are common values. In that case, you need but one scan which you then can process with the tone mapping part of the HDR procedure.

 

Thanks for those hints, Philipp. I had a look at Epson Scan, which does indeed offer degrees of brightness and contrast. I normally use tiff@16bit for BW negs, with Vuescan. I'll experiment with the Epson software and see how it works out.

 

David

[stunsworth]

Vuescan allows you to override the exposure - either up or down.

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You then can set the contrast setting to low ...

 

Change that to "high", obviously.

[andybarton]

I have done multiple scans of the same image (a slide in my case) using Vuescan before. IIRC, you don't need to rescan every time, but once it has been scanned in at full res, you can save several different versions of the file in memory, with the levels and exposure sliders adjusted as you wish.

 

There's no reason why you shouldn't be able to do this with a negative too, of course.

[DavidStone]

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Vuescan allows you to override the exposure - either up or down.

 

Right - but where do I find this option?

(I have the current version of Vuescan and I'm using the "Advanced" and not the "Basic" setup.)

 

David

[DavidStone]

I have done multiple scans of the same image (a slide in my case) using Vuescan before. IIRC, you don't need to rescan every time, but once it has been scanned in at full res, you can save several different versions of the file in memory, with the levels and exposure sliders adjusted as you wish.

 

There's no reason why you shouldn't be able to do this with a negative too, of course.

 

I'm obviously missing something here (I knew that already) but I can't locate these sliders.

 

David

[andybarton]

I'm just about to do you some screenshots...

[andybarton]

OK. Here's my screen with the straight scan from a b&w negative.

 

[ATTACH]228475[/ATTACH]

 

And here's the adjustment to the brightness slider at 0.5

 

[ATTACH]228477[/ATTACH]

 

And here at 2

 

[ATTACH]228476[/ATTACH]

 

The straight scan, with no further PS work (apart from a very small level adjustment at the bottom end) is here

 

[ATTACH]228478[/ATTACH]

 

And after running the three scans as shown above through PS's HDR mode, this is the result. Again, the same minor levels tweak was done. Nothing else.

 

[ATTACH]228479[/ATTACH]

 

I'm not convinced that a better job couldn't be done using normal PS techniques.

 

Obviously, this isn't a particularly challenging negative, but it was on the top of my pile this evening.

[DavidStone]

Thanks Andy. I'm now getting the message.

 

My switch from film to digital, with all its possibilities and complexities, is taking much longer than I'd anticipated, and I'm finding that "keep it simple" is not always a possibility. I don't have Photoshop. I'm increasingly standardising on Lightroom 3, and I've now got all the Nik stuff, including their HDR module. That's a lot to digest.

 

And I have a LOT of negs. - hence my original question. I'll now go off into a quiet corner and see if HDR can squeeze more out of some of my negs than I could in the darkroom.

 

Thanks again

Au revoir

David