RE: filmscanners: VueScan and white pixel clipping SS4000

["Frank Nichols" <frank@theNichols.net>]

I find that the default gama of 2.2 is too high for most of my scans - try
lowering the gama. I use 1.5 to 1.8 normally.

Also, the white point % determines what percentage of pixels in the image
are at 255/1024... (max value). So I normally set this to 0.05 and adjust in
Photoshop where I have a histogram to se whats going on.

/fn

(Newbie alert: Above is based on total ignorance...)

-----Original Message-----
From: owner-filmscanners@halftone.co.uk
[mailto:owner-filmscanners@halftone.co.uk]On Behalf Of Stan Schwartz
Sent: Sunday, July 08, 2001 10:07 AM
To: Filmscanners (E-mail)
Subject: filmscanners: VueScan and white pixel clipping SS4000


I am making a scan of an array of bright azaleas using VueScan and an
SS4000. I am scanning at 48-bits.

I am not sure I understand the settings correctly in VueScan. My scanned
images are showing a lot of burned out highlights. The Photoshop histogram
shows a lot of bright pixel clipping off the the right side of the
histogram, confirmed by Option_clicking the white triangle.

I tried scanning in both white balance and autolevels. The Help information
says that I would be best with autolevels for this type image.

Looking at other high brightness images, it appears I am getting a
significant amount of clipping if I leave the white point setting at 0.5%.
Even at white point set to 0.0%, there is a small amount of white pixel
clipping.

I am not clear what is accomplished by having the white point setting
defaulted to 0.5%.

One other thing the histogram shows: across the top of the histogram, even
before I make any level adjustment, I am seeing about a dozen or so
"whiskers". I understand why these show up after levels adjustments, but I
am not clear why I am seeing them on the unadjust image.

This clipping and the "whiskers" are not showing up when I scan with
Polaroid's software.




Stan Schwartz

www.tallgrassimages.com