RE: [APML] Vuescan Raw Files

["Richard Klappal" <klappal@xnet.com>]

I've been using Vuescan for a few years now, and my understanding is the
same as yours.  RAW is RAW, no gamma correction, color corrections, etc.
The only thing that may adjust dynamically for each image are the auto-black
point and white point settings. You can lock exposure to prevent that (I
don't recall for sure, and didn't see it in a quick glance at the user's
manual).

Subsequent "scanner" processing would be handled using any
adjustments/corrections you feel are appropriate, except that you scan from
the raw file rather than scanning thru the scanner.  Reading from disk is
FASTER than reading from the scanner and you don't have to rehandle the
negs/images.

Vuescan controls my Epson Perfection 2400 PHOTO, and PictureWindow does most
of my image processing.

(std disclaimers ...)

Richard

-----Original Message-----
From: astro-photo-bounces@seds.org
[mailto:astro-photo-bounces@seds.org]On Behalf Of Rodney Watters
Sent: Saturday, 25 December, 2004 17:03
To: Discussion of Film Astrophotography
Subject: [APML] Vuescan Raw Files


A question for the more experienced Vuescan users out there or, more to the
point, I want to confirm some conclusions that I have made and processes
that I have been using.

I have been using the Vuescan raw file option as I like the idea of
capturing the raw data off the media and then hopefully not have to scan the
orginal media again. The basic work flow procedure that I follow is to:

1. Scan slide/negative using the Vuescan "raw scan" mode as 48 bits and save
as TIFF file. I also make sure to set the number of samples to "16" to
reduce scanner noise in the output.
2. Set the Vuescan software to "scan from file".
3. Scan the raw file after checking the black/white points and colour
settings in Vuescan.
4. Save the scanned file for later processing in Photoshop.

For step 3 when scanning the file from disk, I use the following variables:
- For transparencies I set the media on the Input Tab to "image" and the
colour balance on the Color Tab to "neutral".
- For negatives I set the media on the Input Tab to "color negative" and the
colour balance on the Color Tab to "white balance".
- The only black/white point adjustments that I usually find necessary in
step 3 is to maybe adjust the black point a little whilst still leaving
sufficient room on the left hand side of the histogram to allow for later
processing in photoshop without clipping the black levels.

The above process is based on data in Jerry Lodriguss's e-book, APML member
postings and the Vuescan help files.

One key conclusion that I have made which I would like confirmed is to do
with the settings for the Raw Scan. Given that the Raw Scan step is supposed
to be taking the raw data from the CCD in the scanner and to my
understanding saving this raw data unprocessed in a file, then it would seem
that the settings in the Crop, Filter and Color Tabs are not used. The above
being the case I have not been paying attention to them when doing Raw
Scans.

For Raw scans I simply make sure that the settings in the Input Tab and the
Output tab are correct and start the scan.

I would appreciate feedback from the more experienced Vuescan users both on
the process that I am using and my conclusions regarding the settings for
the Raw Scan process.

Many thanks,
Rodney Watters

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