[filmscanners] RE: Lack of contrast in the (raw) scans from VueScan ?

[michael shaffer]

Sassan writes ...

> 
> I am saving B&W images as 16bit tiff gray scale.  Should these be
> saved as 48bit ?

  48bits implies color (3 16bit channels).  Save your b/w scans as 48bits
only if you want to artificially add color.

> ...
> Is there also a manual exposure control (similar to Analog Gain under
> NS ?)

  RGB exposure on the "device" tab.  Set it to 'manual'

> What is the auto-exposure algorithm being used and, other than
> the whitepoint/blackpoint selection which essentially clips/stretches
> the tonal range, how does one adjust ("center") the exposure to match
> the mid point of the density distribution of the film durin the scan ?

  I believe (without knowing exacty) Vuescan effectively and automatically
sets the exposure for the density of the film, and the histogram for the
"raw" scan is a direct result of the hardware (CCD).  Whether or not you
want the histogram stretched or shifted is done in software with the "color"
tab. Use it to your liking, or do the same thing in Photoshop.

  You can, however, obtain some interesting effects, if not obtain better
detail in the denser regions of the film, by increasing the exposure.
(note: I am speaking of using Vuescan with color negs, and assuming it works
the same.)

cheerios ... shAf  :o)
Avalon Peninsula, Newfoundland
www.micro-investigations.com


Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners'
or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body

[filmscanners] Re: Lack of contrast in the (raw) scans from VueScan ?

[Sassan Hazeghi]

 > From: Bob Shomler <[EMAIL PROTECTED]>
 > 
...
 > Vuescan is, as you have written, designed to get all that the scanner can get from 
 >film.  Default black and white point settings extend far wider than you might want in 
 >a final image.  Changing Vuescan's color white and black point percents can help 
 >here.  However having Vuescan save 48-bit mode tiff and making these adjustments in 
 >Photoshop 16-bit mode is preferred by many.  (This is what I do with my LS-30 scans.)

I am saving B&W images as 16bit tiff gray scale.  Should these be
saved as 48bit ?

 >
 > If you're using 7.5 (beta or no point release) you need to get a newer release.  
 >Some significant "dull image" problems were fixed in 7.5.2.  If you're at 7.5.11 or 
 >later you're probably OK, otherwise download the latest (7.5.22).

Thanks much for the hint; 7.5.14 seems to do much better !

 > Set Device->Option Types to advanced to see many of the controls, such as for 
 >exposure (which will be found in the device tab).
 >
 > Also check out the Advanced Workflow Suggestions in the Vuescan help file.
...

Is there also a manual exposure control (similar to Analog Gain under
NS ?)  What is the auto-exposure algorithm being used and, other than
the whitepoint/blackpoint selection which essentially clips/stretches
the tonal range, how does one adjust ("center") the exposure to match
the mid point of the density distribution of the film durin the scan ?

Thanks,
Sassan.


Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners'
or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body

[filmscanners] Re: Lack of contrast in the (raw) scans from VueScan ?

[Bob Shomler]

At 10:55 PM 4/27/2002 -0700, you wrote:
>I have had a Nikon LS-30 scanner for over a year now and until
>recently it was being used occasionally to scan images that I needed
>to post to a web page or send via email. A couple of months ago,
>though, I started looking into how to capture the "most" from my films
>for archival purposes and was surprised by the initial results from
>using VueScan (which I had hoped would give me more than the 8bit
>pixel depth I am getting from NikonScan.)
>
>I am using VueScan 7.5 (beta ?) and NikonScan 3.1.0, and the "default"
>settings for VueScan generally produces images that are washed out and
>lack in contrast.  ...Are there any obvious
>controls for VueScan that I need to be changing (other than the film type
>& scan resolution -- I don't seem to be able to find a manual exposure
>or Analog Gain control.)

Vuescan is, as you have written, designed to get all that the scanner can get from 
film.  Default black and white point settings extend far wider than you might want in 
a final image.  Changing Vuescan's color white and black point percents can help here. 
 However having Vuescan save 48-bit mode tiff and making these adjustments in 
Photoshop 16-bit mode is preferred by many.  (This is what I do with my LS-30 scans.)

If you're using 7.5 (beta or no point release) you need to get a newer release.  Some 
significant "dull image" problems were fixed in 7.5.2.  If you're at 7.5.11 or later 
you're probably OK, otherwise download the latest (7.5.22).

Set Device->Option Types to advanced to see many of the controls, such as for exposure 
(which will be found in the device tab).

Also check out the Advanced Workflow Suggestions in the Vuescan help file.

I assume in this that your reference to raw files is to the Vuescan "Save TIFF File" 
results, not the raw scan data from the scanner (Files->Save raw file), which will 
look flat (and negative inverted for neg film).

>- Can VueScan reliably/repeatably get 10bit raw readouts of a given
>  pixel or are the extra two bits simply random values being read
>  independent of the value of the pixel ?

AFAIK the 10 bits are what the scanner delivers.  I have not had problems with this on 
my LS-30.  You sometimes can get a little improvement (noise reduction) by setting 
Device-> Number of passes to 2.  See also the "Maximizing Image Quality" section of 
the help file.

Bob Shomler
www.shomler.com


Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners'
or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body

[filmscanners] Re: Lack of contrast in the (raw) scans from VueScan ?

[Maris V. Lidaka Sr.]

This is how Vuescan is designed to work - to NOT clip any highlights or
shadows, but to leave that for postprocessing in PS or other program where
you can examine the image more closely and determine what if any endpoint
clipping to do, and set your black and white point with much more accuracy.

On the Device tab be sure your selection for "Option types" is advanced -
that will give you the full controls.

On the Color tab you can experiment with Color balance, Black point and
White point, and the Brightness controls.

Maris

- Original Message -
From: "Sassan Hazeghi" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Sunday, April 28, 2002 12:55 AM
Subject: [filmscanners] Lack of contrast in the (raw) scans from VueScan ?


I have had a Nikon LS-30 scanner for over a year now and until
recently it was being used occasionally to scan images that I needed
to post to a web page or send via email. A couple of months ago,
though, I started looking into how to capture the "most" from my films
for archival purposes and was surprised by the initial results from
using VueScan (which I had hoped would give me more than the 8bit
pixel depth I am getting from NikonScan.)

I am using VueScan 7.5 (beta ?) and NikonScan 3.1.0, and the "default"
settings for VueScan generally produces images that are washed out and
lack in contrast.  This is particularly pronounced for B&W negatives
(TMY-400 & Tri-X) where the histograms for the raw scans show ~10
points less std deviation than the scans produced by the (default
settings for) NikonScan.  The lack of contrast is also present, though
not as pronounced, when comparing the scans for T400-CN (C-41 B&W
film) as well as color negatives or slides.  Are there any obvious
controls for VueScan that I need to be changing (other than the film type
& scan resolution -- I don't seem to be able to find a manual exposure
or Analog Gain control.)

I have placed the JPG form of the scan files from NikonScan, VueScan
and raw fladbed scans from 4x6 prints (from the local lab) of a couple
of Tri-X and one T400-CN negative under the attached URLs (sorry about
the large files) and would appreciate any insight into what I may be
doing wrong as well as the answer to any of the the listed
questions I have run into, in the course of this exercise.

Thanks,
Sassan.

Tri-X

http://63.197.150.190/sassan/photography/test-scans/Heidesee-pumphouse-Nikon
Scan.jpg

http://63.197.150.190/sassan/photography/test-scans/Heidesee-pumphouse-ViewS
can.jpg

http://63.197.150.190/sassan/photography/test-scans/Heidesee-pumphouse-print
.jpg

Tri-x

http://63.197.150.190/sassan/photography/test-scans/Heidesee-boathouse-Nikon
Scan.jpg

http://63.197.150.190/sassan/photography/test-scans/Heidesee-boathouse-ViewS
can.jpg

http://63.197.150.190/sassan/photography/test-scans/Heidesee-boathouse-print
.jpg

T400-CN

http://63.197.150.190/sassan/photography/test-scans/Village-after-Lentsch.Ni
konScan.jpg

http://63.197.150.190/sassan/photography/test-scans/Village-after-Lentsch.Vi
ewScan.jpg

http://63.197.150.190/sassan/photography/test-scans/Village-after-Lentsch.pr
int.jpg

And the questions ...

- What is the appropriate film (media) setting for T400-CN ("color
  negative" or "B&W negative") under either software ?

- Likewise, how does one disable "autoexposure" entirely (NikonScan
  allows changing the Analog Gain but this seems to be changing the bias
  to the autoexposure readout. )

- Can VueScan reliably/repeatably get 10bit raw readouts of a given
  pixel or are the extra two bits simply random values being read
  independent of the value of the pixel ?  I.e. Does a full resolution
  scan of Q60 produce a tiff file that matches that of LS-40 ?

- Related to the above tow back-to-back scans of the same image
  (without any change to the registration of the film) seem to always
  produce scan files that differ measurably, if not  significantly. I
  realize that compared to digital logic, CCD's can be more temperamental
  but I am wondering, if this is more noticeable in LS-30 compared
  to LS-40 or LS-4000 or they all use a similar CCD array ?

- If I need to switch to a more capable scanner for consistent
  "archival" scans, beyond the auto slide-feeder, does LS-4000
  offer real advantages over LS-40 ?  More specifically:
  - Does LS-4000 cope with Kodachrome any better than LS-40/30 ?
  - Is the digital ICE capability of the LS-30 and LS-40 comparable ?
  - Is the Firewire interface in LS-4000 noticeably faster than
LS-40's USB ?

- On a different type of question, how does one view the (density/
  luminescence) histograms for two images side-by-side under PS 6.0 ?
  This seems to be a very basic and useful operation but it is not
  obvious how to display the histogram for the second image without
  closing the first one !




Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe
filmscanners'
or 'unsubscrib

[filmscanners] RE: Lack of contrast in the (raw) scans from VueScan ?

[michael shaffer]

Sassan writes ...

> ...
>
> I am using VueScan 7.5 (beta ?)

  Update your version of Vuescan.  Vs versions later than 7.5.14 are very
solid with all Nikons.  ...

> ... and NikonScan 3.1.0, and the "default"
> settings for VueScan generally produces images that are washed out and
> lack in contrast.  ...

  Keep in mind Vuescan tends to capture all information available in the
film, and  would therefor naturally yield an image rather flat.  Its default
setting for whitepoint is 1% and for blackpoint zero%.  These settings
assume 1% of the pixels are specular highlights, and then captures all pixel
values.  I happen to believe whitepoint should be less (~0.1%), but I
believe you'll notice a big difference if you set your Bp at some similar
value.

cheerios ... shAf  :o)
Avalon Peninsula, Newfoundland
www.micro-investigations.com


Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners'
or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body