RE: [APML] Alternative Anti-Vignetting Photoshop Technique

["George Whitney" <gwhitney@maine.rr.com>]

Jeff,
The best way to fix uneven illumination is by flat fielding, just like in
CCD photography.  Photograph an evenly light square of white foam core
through an opal glass using a continuous tone film, reverse the image in
Photoshop, and stack the result with your scanned image and...presto...no
vignetting!
George



-----Original Message-----
From: owner-astro-photo@seds.org [mailto:owner-astro-photo@seds.org]On
Behalf Of Jeff Ball
Sent: Monday, January 07, 2002 1:44 PM
To: astro-photo@seds.org
Subject: RE: [APML] Alternative Anti-Vignetting Photoshop Technique


Hello Tom,
Thanks for the av procedure.  I tried it on an image that had uneven
illumination in the corners.  That is my main problem.  It helped
tremendously.  I am still learning how to maximize the procedure, but early
results look good.  Thanks for passing along.  I need simple directions in
PS.  Here is the first image I have worked with.

http://www.astro-photography.com/cirrus.htm

Jeff Ball
www.astro-photography.com
Ohio Valley Astronomical Society
www.ovas.org


-----Original Message-----
From: owner-astro-photo@seds.org [mailto:owner-astro-photo@seds.org]On
Behalf Of T&JDiana
Sent: Monday, January 07, 2002 2:00 AM
To: astro-photo@seds.org
Subject: [APML] Alternative Anti-Vignetting Photoshop Technique


Greetings all,

I have decided to rejoin the list after nearly a year hiatus.  I have been
experimenting with different techniques to correct for vignetting and wanted
to share one with you.  I would appreciate any feedback.

http://www.astronomyphotos.com/PhotoshopTechniques2.htm

Thanks much,
Tom


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