I'm by no means an expert on image manipulation. If experts recommend to
do despeckle as last step, then perhaps that might be best.
My logic was that a noisy image would be harder to scale right because
the noise could introduce more artifacts. But I could be wrong -- I
don't have that much experience, and don't have time now to do the
experiments. (Would first need to search for a suitable photo...).
However, I thought that if you already have a number of photos at hand
to experiment with, then it might be a quick experiment for you to first
reduce noise in the image, then perhaps sharpen it, and then scale it.
About quality of ImageMagik vs. GIMP, I have no idea. I never made a
detailed comparison of the two in quality of scaled image.
I did make a comparison of scaling of ImageMagik and PIL (Python Imaging
Library) and found them to be comparable for the photos I needed to
rescale at that point; after which I wrote my script in Python using PIL
to scale down (without any further enhancements) a full copy of all
images from my digital camera to fit my screen. But, as I said, they're
images from a digital camera and not from a scanner. And I didn't care
if a single image would come out with poor quality; it was a massive
At that point I had already given up on writing a GIMP script to perform
this operation in batch so I didn't compare the quality of GIMP scaling
with the others.
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