VueScan & raw files

[Gour]

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[Henk de Jong]

the following text:

Hi!

Yesterday while googling I found an old thread in pcreview's forums
named "VueScan raw file is not a true raw file!". Tried to post there
'cause it was too old to be found on news server, but since I did not
receive any reply I'm reposting here...

I'm new Epson V700 user preparing to batch-scanning ~2500 slides and the
old thread was discussing whether VueScan apply some processing on its
faw files...

<quote>
Originally Posted by Henk de Jong

My conclusion is:
1)
With ICC Built-in profiles the raw files with "Raw output with: Scan" and
"Raw output with: Save" are identical and with good colour.
2)
With a self made ICC profile (from a Wolf Faust slide) the "Raw output
with:
Save" has a wrong colour and the one with the "Raw output with: Scan" is
okay.
</quote>

Is the above statement correct?

I plan to scan 35mm slides in 4800 dpi and archive them on HD/tapes for
usage in video 'slide-show' projects later.

In several places on the Internet I read about the possible problem when
using 'Raw output with: Save' and that's why plan to use 'Raw output
with: Scan'.

However, I've W. Faust's targets, but would like to skip
calibrating-monitor and profiling-scanner steps and just do 'raw batch
scan' and then re-scan from files in Vuescan (after I'd calibrate my
monitor and profile the scanner) to do post-processing phase and
applying scans to ICC profiles.

Few questions:

* is the above workflow correct?

* is it confirmed that using built-in ICC profile provides that
which I need for archiving of my slides?

* is it better to not crop in this phase when doing archiving-scans?

Sincerely,
Gour

I was the original poster of the "VueScan raw file is not a true raw file!".
In July 2004 Ed has responded to my problem. You can read it in the thread
at the bottom of this message.

Is the above statement correct?

Yes and no. Ed Hamrick wrote: "It's best to save the raw file at the same
time as the scan".
But I cannot find this setting in the current VueScan version anymore....

* is the above workflow correct?

It is the same workflow I use.

* is it confirmed that using built-in ICC profile provides that
which I need for archiving of my slides?

I use my own calibration file (ICC Profile) made from a Wolf Faust target
slide. The colours are much better. The built-in profile turns out too red
with my scanner (ScanWit 2720S).

* is it better to not crop in this phase when doing archiving-scans?

I do not crop in VueScan. I do this in Photoshop. Cropping as one of the
last steps have to be done by hand, but produces the largest image after
you have corrected the horizon.
If you do not crop in VueScan, you possibly "scan" black borders when post
processing. To prevent a wrong black point setting choose a Buffer (%)
setting under the Crop tab ( I use 4%).


With kind regards,
Henk de Jong

http://www.hsdejong.nl
Nepal and Myanmar (Burma) - Photo Galleries


-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-

Hi Henk,

Sorry it's taken me so many months to get back to you on this,
but I found out why the two raw files were different.

It turns out that the "Color|Scanner color space" option affects
the raw image data when "Output|Raw output with" is set to
"Save". VueScan produces profiles that attempt to correct for
a non-linear CCD response, and the scanner profile can have
a gamma between 0.95 and 1.05. This non-linearity
correction is being done on the data before being written with
the scan.

It's best to save the raw file at the same time as the scan.

Regards,
Ed Hamrick

P.S. This message is the oldest one in my mailbox, but I didn't
delete it because I was curious why this happened.

Dear Ed,

Thank you for coming back on the issue.
In the end my conclusion was right: "VueScan raw file is not a true raw
file" under the condition that you save the raw scan file with the option
"Output|Raw output with" is set to "Save".
It took me a long time and experimenting to discover when I produced the
right raw file and when the wrong. Fortunately I had not archived any wrong
raw file slide scan

It's best to save the raw file at the same time as the scan.

Yep, that is my current work flow! ;-)

But are you going to do anything about it?
A warning in the help files maybe or are you changing the way the raw files
are saved? After all a raw file is a raw file...

I will remove my scan samples from my website now they are not needed
anymore.

With kind regards,
Henk de Jong

 

[Gour]

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[Henk de Jong]

Output --> Raw output with --> {Save, Preview, Scan}

I'll try with 'Scan' option.

Yes, that is what I use also.

from the help information:
-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-
Output | Raw output with

(Professional Edition only)

This specifies which operations in VueScan cause the raw scan data to be
written to a file.

If set to "Scan" (or "Preview"), the raw file is written at the same time as
the scan (or preview). In this case, the raw file has not had infrared
cleaning or grain reduction applied.

Assuming that the preview is used primarily to prepare for the final scan,
this option should normally be set to "Scan" so that the highest resolution
raw image can be saved.

If set to "Save", it is written at the same time as other files are written
(i.e. after a scan completes or when the "Save" button is pressed). In this
case, the raw file has had infrared cleaning and grain reduction applied.

It's much faster to save the raw file at the same time as the scan, since
writing the file is overlapped with scanning the data.

Advanced Option: This option is displayed when Output | Raw file is set.

Hmm, does it mean that I'd need to calibrate my scanner with W. Faust's
target slide BEFORE starting with the batch scan?

With the above setting I don't think so.

I thought that I can profile my scanner later when doing post-processing
phase from file's raw scan and that raw scan does not apply anything to
raw scan file?

With the above setting the raw files with or without the use of the .icc
profile should be the same.

What about Input --> Lock exposure option? Is it required for raw scans?

I do not know, because my scanner does not support this.

From the help information:
-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-
Input | Lock exposure

Set this option to lock the CCD exposure values to auto-exposure values
computed for the most recent preview or scan, or as adjusted manually with
the Input | RGB exposure option.

This option can save time when scanning a batch of images with similar
characteristics, e.g. a roll of film.

If you turn on this option and also clear Crop | Auto offset and Crop | Auto
rotate, then the "Scan" button will not perform a preview scan. This can
save time when batch scanning.

Note that locking the CCD exposure values doesn't lock the brightness of the
final images - it only locks the brightness of the raw scan files. To lock
the brightness of the final images, use the Input | Lock image color option.

See the "Advanced workflow suggestions" section of this User's Guide for
more information.

Advanced Option: This option is displayed when the scanner can control the
CCD exposure time.

And lastly, do you recommend saving raw scans as *.TIFF or in *.DNG
format?

I prefer TIFF, because almost all programs support this.
But DNG has also advantages.

From the help information:
-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-
Output | Raw DNG format

(Professional Edition only)

This specifies whether to write raw files in DNG (Digital Negative) format.
This allows VueScan's raw files to be read by the Adobe Camera Raw plugin or
other programs that read DNG files.

These DNG format raw files can also be read by VueScan when you set Input |
Source to "File".

Advanced Option: This option is displayed when Output | Raw file is set.
-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-<>-

Please read the VueScan help information. It has a lot of information
provided by the maker himself.


With kind regards,
Henk de Jong

http://www.hsdejong.nl
Nepal and Myanmar (Burma) - Photo Galleries

 

[Gour]

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[Gour]

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