[APML] Anti-vignetting in PS 7

["Greg Hartke" <ghartke@adelphia.net>]

I'm taking advantage of the time off from work to catch up on my processing
backlog. (I haven't done any serious processing in quite a while.) I was
working on anti-vignetting a particular image and developed a strange
problem. I'm sure it's a "duh" problem but I'll be darned if I can figure
out what I'm messing up. Hopefully someone here will be able to set me
straight.

I opened the original image (TIFF, scanned using VueScan) in PS 7. At this
point, the image is 16 bits per channel. I cropped it slightly to a modulo
10 size because I expected to resample the AV mask to 10% size, blur it,
then return it to its original size. I duplicated the image and, working on
the duplicate, applied a median filter to get rid of the stars. I then used
the clone stamp tool to perform further smoothing 'til I was satisfied it
would make a good mask. I then reduced it in size to 10% of its original
size using bicubic sampling, applied a Gaussian blur, then rescaled it back
to its original size, again using bicubic sampling.

At this point, I converted the blurred mask and the original image to 8 bits
per channel so I could use "Apply Image" to subtract the mask (with offset)
from the original. I made the original image active and clicked "Image" ->
"Apply Image". This brings up a dialog box with a few options. The first
thing to do was to change the "Source" to the blurred mask with the target
as the original image. The problem is that the "Source" is the original
image and I can't seem to change it to the blurred mask. The drop-down menu
contains nothing but the original and I can't even type in the name of the
mask.

I've tried this several times (changing the active image, for example) and
can't seem to get past this step. Mind you, I've done this before with
complete success but obviously I've forgotten something trivial that's
messing up my efforts. Anyone have any insight into what I'm doing wrong?

Thanks for the help!

Greg Hartke
Sykesville, MD USA

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