Maybe I wasn't clear.
When I initiate a scan using HP's software (HP document viewer), the
scan looks fine.
This is even if I "Scan to Photoshop" from HP (which basically scans
to bmp, then loads with PS0
When I initiate a scan using Photoshop (TWAIN acquire), the scans look
bad.
It has nothing to do with resolution -- with both scans, I use the
same saved scan profile, which sets exposure, resolution, sharpeneing,
etc. I am comparing both in photoshop using a large magnification.
The problem is subtle (but present) for photos. The problem is really
obvious for greyscale text, where basically you've got thin lines.
The photoshop initiated scan basically breaks these lines up into
dots, as if they were being over sharpened, or as if the brightness
and contrast were both cranked way up. The HP initiated scan looks
like the preview, and in fact like the original document, where
continuous lines are continuous shades of grey.
The histograms show a drop on the midtones of the Photoshop initiated
scan -- darks get darker, lights get lighter.
My one thought was maybe this is some sort of gamma effect, though I
have tried this with and without adobe color correction turned on. I
guess I need to try TWAIN acquires from some non adobe or HP software,
to figure out who is causing the problem.
-JB
