****big cheese**** wrote:
No, these TIFFS were presharpened, either by unsharp
masking, wavelets, or blind deconvolution, and ended up
with artifacts. Perhaps I should try enlarging first
and then applying sharpening. I still have the original
unsharpened TIFFs/ RAWs still available.

Always resample first and only second sharpen to taste
by inspection. If you downsample (e.g., for the web) it
is most likely that Unsharp Mask will be more effective
than Sharpen, though both will likely be useful.

If you upsample (as you are describing), you'll usually
find Sharpen has more effect than Unsharp Mask, but
again both might be useful.

Resampling uses filters that have different effects.
That is how "bicubic sharper" and "bicubic smoother"
differ. Generally a slight amount of "ringing", or
sharpening, is useful when downsizing, while not so much
when upsizing. But bicubic is not particularly good.

The best program that I know if is the ImageMagick tools
package. Generally you can resample like this:

convert inputfile.jpg -depth 16 -gamma 0.454545 \
-resize 6000x4000 -quality 89 -gamma 2.2 -depth 8 \
-density 360 -units PixelsPerInch outputfile.jpg

The default filter for upsizing is Mitchell and for
downsizing is Lanczos. The input and output files can
be JPEG, TIFF or other standard file formats. If TIFF
is the output format then an option "-compress ZIP" can
be used (or LZW compression can be specified).

Note that two very significant aspects of the above
command (beyond the much superior filtering, which can
also be selected from a couple dozen options), is that
files are first converted to 16 bit depth and to a
linear gamma, and then resized and converted back to
gamma 2.2 and 8-bit (that option can be removed for JPEG
or for a TIFF if 16-bit depth is the desired output).

If you want to see the various filters, "compress -list filter"
will show what is available. To learn some of the technical
details use Google to search for the two words "Robidoux filter"
which will turn up articles by Nicolas Robidoux on his research.

--
Floyd L. Davidson http://www.apaflo.com/
Ukpeagvik (Barrow, Alaska)