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Author Topic: How to get a flat scan from Vuescan?  (Read 4186 times)

aaronchan

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How to get a flat scan from Vuescan?
« on: December 13, 2012, 05:17:02 am »

Dear all,

I've bought the Vuescan bible and bought the lastest Vuescan at the same time.
I'm trying to scan a few cloud B&W negatives from my 4x5 camera.
When I do the preview, Vuescan will automatically compress my range to 0 - 255.
I've played around in [input] & [color] to try to get a flat look which would be more realistic to the original scene.
But I still can't fix the shadow part, my histogram looks very broad rather than so narrow.
Is there anyway turn the black into some kind of dark gray during the scanning procedure in Vuescan?

Thanks
Aaron

TimG

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Re: How to get a flat scan from Vuescan?
« Reply #1 on: December 13, 2012, 09:39:54 am »

Aaron,  have you tried contacting Ed Hamrick directly?  He offers technical support via email and is generally very quick to respond.
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dmerger

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Re: How to get a flat scan from Vuescan?
« Reply #2 on: December 13, 2012, 02:52:43 pm »

Aaron, it’s been a while since I used VueScan, so I can’t answer your question, but have you ever tried to scan your B&W negatives as positives (either normal 16 bit or 16 bit linear), then inverted in PS or LR?  I’d guess that both would give you a much narrower histogram and let you (instead of VueScan) decide how to render the image initially. Of course, with 16 bit linear you’d also need to make a gamma adjustment, but again you’d have control over it.  I’ve not tried this approach myself with B&W negatives, so all I’m doing is raising a possibility.

By the way, do you pronounce your name A – A- Ron? 

http://www.youtube.com/watch?v=Dd7FixvoKBw
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Dean Erger

aaronchan

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Re: How to get a flat scan from Vuescan?
« Reply #3 on: December 14, 2012, 03:41:31 am »

For the record, here is what i get.

Bart_van_der_Wolf

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Re: How to get a flat scan from Vuescan?
« Reply #4 on: December 14, 2012, 04:26:17 am »

Dear all,

I've bought the Vuescan bible and bought the lastest Vuescan at the same time.
I'm trying to scan a few cloud B&W negatives from my 4x5 camera.
When I do the preview, Vuescan will automatically compress my range to 0 - 255.

Hi Aaron,

The 0 -255 range is a result from your choice of 'Input' tab parameters. When you set the 'Bits per pixel' to 8 bit gray, then the resulting output data from the scanner wil be a single gray channel file with 8-bit data. VueScan will usually acquire the data directly from the scanner as linear gamma data, which will then be adjusted according to the settings of the 'Color' tab, such as clipping points, brightness, and gamma.

In the case of an 8-bit per channel data input setting, it is possible (depending on the scanner firmware) that the scan data (which is originally in 12 to 16-bit per channel inside the scanner) is already leaving the scanner as gamma adjusted 8-bit data with the use of a a lookup table in the scanner's firmware. Doing the gamma adjustment in 12 to 16-bit and then convert to 8-bit is to avoid loss of precision when the linear 8-bit data would require significant gamma adjustment later in software. VueScan is clever enough to choose the method that produces the best quality.

Quote
I've played around in [input] & [color] to try to get a flat look which would be more realistic to the original scene.
But I still can't fix the shadow part, my histogram looks very broad rather than so narrow.

I'm not exactly sure what you want to achieve by 'fixing the shadow part', but you should probably make sure that on the 'Color' tab your Black point clipping is at 0%, and your white point clipping is at a setting that just avoids clipping if you want contrast in the clouds, or the White clipping point is set at 100% (=1) if you want to keep a more moderate cloud contrast.

Quote
Is there anyway turn the black into some kind of dark gray during the scanning procedure in Vuescan?

The 'Brightness' controls are just gamma adjustments, so you may need to use a dedicated image editor instead of a Scanner utility to position the darker end of the histogram at a default higher level.

Cheers,
Bart
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== If you do what you did, you'll get what you got. ==
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