Re: unsharp mask?

In article <bbodd152jesbue04kq6klka9dl7ccdc40v@xxxxxxx>, Hecate <hecate@xxxxxxxxxxx> writes 

I'm not just disagreeing with you on "the fact that a filter can be
used badly" I'm disagreeing with you on whether the filter can be used
at all with anything less than resulting, and obvious, sharpening
artifacts, except in very small doses on specific small objects with a
much larger image.  The difference with USM is that, used properly,
USM will give you a reasonable result across a whole image -
particularly where you are correcting for the inherent softness of RAW
files. Applying sharpen to a whole image just results in a mess.

And I am disagreeing with your statements that it always results in sharpening artefacts and a mess - that certainly is NOT true. Whilst the effect of these filters may result in some artefacts with images which are undersampled in the first place, by producing an MTF which exceeds unity, that certainly is not the case in general. In fact, I have yet to see a *single* instance of "sharpening artefacts" caused by the application of the standard level of the sharpening filter even to images downsampled from raw scans. I have certainly seen many instances where "sharpen more" was excessive and produced artefacts, but I have also seen images where even that level does not produce any noticeable issues. Applying these filters to the output of a flatbed scanner, for example, certainly will not "result in the mess" that you predict.

Yes, you have a problem using them and the standard levels are, by no means, as flexible as the USM, but your claims are ridiculously exaggerated.
--
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A lovely little thinker, but a bugger when he's pissed.
Python Philosophers (replace 'nospam' with 'kennedym' when replying)
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Relevant Pages

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