vuescan - how to process raw files correctly?

[ddtl]

Hello everybody,

I used vuescan 8.0.14 to scan black/white documents using
Epson 2400.

In order to be able to scan quickly, I had set 'Output' to
'Raw file', and had used following options (AFAIK, those are the
most important ones):

Input:
task: scan to file
source: perfection2400
media: text
bits per pixel: 1 bit b/w
preview resolution: 300dpi
scan resolution: 300dpi
auto save: scan

Output:
raw file type: 1 bit b/w
raw output with: scan

Options on Filter & Color tabs were left unchanged.

Then I tried to process the raw scans - changed 'source' to
'file', set 'mode' to 'flatbed', 'preview/scan resolution'
to 'custom' (300 dpi), and pressed the 'scan' button. But when
I looked at the resulting images, I saw that no processing was
done.

If instead of 'raw file' as an output I select 'tiff file',
scans are neatly cleaned and have a much smaller size (up
to twice). In that mode, I have to wait around 10 seconds
between scans while vuescan processes the scanned image,
but the scanning itself takes the same amount of time as
when 'raw file' is set as an output.


What can I do so that vuescan will process the raw files
in the same way it processes scans when 'tiff file' is
set as an output?

 

[Alan Smithee]

Hello everybody,

I used vuescan 8.0.14 to scan black/white documents using
Epson 2400.

In order to be able to scan quickly, I had set 'Output' to
'Raw file', and had used following options (AFAIK, those are the
most important ones):

Input:
task: scan to file
source: perfection2400
media: text
bits per pixel: 1 bit b/w
preview resolution: 300dpi
scan resolution: 300dpi
auto save: scan

Output:
raw file type: 1 bit b/w
raw output with: scan

Options on Filter & Color tabs were left unchanged.

Then I tried to process the raw scans - changed 'source' to
'file', set 'mode' to 'flatbed', 'preview/scan resolution'
to 'custom' (300 dpi), and pressed the 'scan' button. But when
I looked at the resulting images, I saw that no processing was
done.

What kind of processing did you apply or what did the results look like?
Also because your preview and scan resolutions are set the same you won't
see any quality difference between the two.

If instead of 'raw file' as an output I select 'tiff file',
scans are neatly cleaned and have a much smaller size (up
to twice). In that mode, I have to wait around 10 seconds
between scans while vuescan processes the scanned image,
but the scanning itself takes the same amount of time as
when 'raw file' is set as an output.

Not sure what "cleaned" means exactly. Could describe it more. The tiffs are
smaller probably because "auto" is still selected under tiff compression.

What can I do so that vuescan will process the raw files
in the same way it processes scans when 'tiff file' is
set as an output?

OK. A Raw file IS a tiff file (more or less). It sounds like you are trying
to output RAW --> RAW. In most instances VueScan users use Raw format as a
means of preserving the exact image that the CCD recorded so color
corrections, filters et al can be applied as circumstances dictate or
reapplied at a later date.
What is the exact nature and scope of the project you are scanning?

 

[Alan Smithee]

I scanned a book using your settings on an Epson 3200 and mine came up
clean. I'm wondering if it could be something to do the the paper which is
being scanned. What about the "Color" tab. I can produce similar results as
yours by changing the color balance to Manual and then moving the white
point slider. It's got to be either be a contrast adjustment being
introduced or the White Point is being repositioned is my best guess. Very
odd.

 

[ddtl]

What kind of processing did you apply or what did the results look like?
Also because your preview and scan resolutions are set the same you won't
see any quality difference between the two.

In order to be able to explain myself correctly, I made a scan for an example.
I configured vuescan to output both 'tiff file' and 'raw file', and used the
following options:

http://xt.nm.ru/scaner.ini

I also made screen capture of the options' tabs (size of each screen
capture ~30Kb):

'Input' tab: http://xt.nm.ru/input_scanner.jpg
'Crop' tab: http://xt.nm.ru/crop_scanner.jpg
'Output' tab: http://xt.nm.ru/output_scanner.jpg

Options on the rest of the tabs weren't changed (I left the default settings,
except for disabling 'External viewer' on 'Prefs' tab).

Here is what I got after scanning a page from a book:

The 'raw file' (168Kb):
http://xt.nm.ru/raw0001.tif

The 'tiff file' (83Kb):
http://xt.nm.ru/tiff0001.tif

As you can see, in the 'tiff file' the black strip in the middle
is much narrower, the characters are much clearer, and generally
the image contains much less black dots than the 'raw file'.

Interesting thing - after each scan, vuescan displays the result
in the 'Scan' tab. That result looks exactly like scaled down version of
'tiff file', and not like 'raw file' - even if vuescan is configured to
output only 'raw file' (that is what actually had caused me to notice that
something was amiss - after I saw that the results I was getting are much
worse than what is shown in 'Scan' tab).



Next, I tried to process the 'raw file'. Here are the options I used for that:
http://xt.nm.ru/file.ini

Or, screen captures of options' tabs:

'Input' tab: http://xt.nm.ru/input_file.jpg
'Crop' tab: http://xt.nm.ru/crop_file.jpg
'Output' tab: http://xt.nm.ru/output_file.jpg


The result was exactly like 'raw file' I got after scanning, even their
md5sum matched, which means that no processing was done.

Also, after processing, 'Scan' tab showed scaled down version of 'raw file'.

 

[Alan Smithee]

It doesn't look so - with other books I get the same result, though
when book's paper quality is low, the difference between 'raw file'
and 'tiff file' is much more pronounced, because with a good paper
there is less to clean.

Also, conceptually paper type shouldn't matter - if vuescan can clean
the image (and it certainly could), then shouldn't it be able to do
the same to the raw scan?


I will try to experiment with this (I am away from the scanner right
now), though I would certainly prefer to use vuescan's default
processing (applied to 'tiff file'), because it's creator is a professional,
which means that the options he had choosen are the best ones for
most jobs.

Can it be some incompatibility with a scanner (Epson 2400), maybe?
Did any owner of that model encounter the similar problem?

 

[Alan Smithee]

It doesn't look so - with other books I get the same result, though
when book's paper quality is low, the difference between 'raw file'
and 'tiff file' is much more pronounced, because with a good paper
there is less to clean.

The "cleaning" effect is simply a matter of having the correct amount of
contrast to render the blacks black and the whites white. I'm guessing that
the scanner is capable of natively sampling at one bit. You might want to
try scanning the images as 8 bit black and white and then saving them as
Tiffs as 1 bit files.

 

[ddtl]

I scanned a book using your settings on an Epson 3200 and mine came up
clean. I'm wondering if it could be something to do the the paper which is
being scanned.

It doesn't look so - with other books I get the same result, though
when book's paper quality is low, the difference between 'raw file'
and 'tiff file' is much more pronounced, because with a good paper
there is less to clean.

Also, conceptually paper type shouldn't matter - if vuescan can clean
the image (and it certainly could), then shouldn't it be able to do
the same to the raw scan?

What about the "Color" tab. I can produce similar results as
yours by changing the color balance to Manual and then moving the white
point slider. It's got to be either be a contrast adjustment being
introduced or the White Point is being repositioned is my best guess. Very
odd.

I will try to experiment with this (I am away from the scanner right
now), though I would certainly prefer to use vuescan's default
processing (applied to 'tiff file'), because it's creator is a professional,
which means that the options he had choosen are the best ones for
most jobs.

Can it be some incompatibility with a scanner (Epson 2400), maybe?
Did any owner of that model encounter the similar problem?

 

[ddtl]

The "cleaning" effect is simply a matter of having the correct amount of
contrast to render the blacks black and the whites white. I'm guessing that
the scanner is capable of natively sampling at one bit. You might want to
try scanning the images as 8 bit black and white and then saving them as
Tiffs as 1 bit files.

Indeed, you was right - I tried to scan with 1 bits per pixel,
setting 'raw file type' to 8 bits, and after that vuescan was able to process
the resulting raw file as I had expected! Though now those raw files
take up 70 times more HD space than before, but well, nothing can be
perfect.

And thanks for your help!