Very often the case and much scientific progress has been made over the centuries on the basis of that very principle. BUT in this particular instance we are not dealing with beliefs. We are dealing with algorithms that emerged from very extensive testing done by people who seriously knew/know the subject matter, and I respect that. That said, there's little in this world that can't be improved upon, but I think scientific procedure pretty much requires that you identify and demonstrate lacunae in the approach you are challenging, as a basis for trying to achieve the same objective in a better way. That is why I recommended Jeff's book to you.
I looked at the article you referenced and I didn't see, even at 200% magnification the kind of damage you consider to be "criminal" at 50 or 60 Amount setting. Personally, I don't usually find it necessary or desirable to move much beyond 45, but it can happen if I also added luminance noise reduction. However, give or take 10 or 15 point of Amount, there is something intervening called "taste". What you may consider "criminal" someone else may think is just sharp and snappy. It only gets criminal if anything has been destroyed, but if you use PK Sharpener (unflattened) or Lightroom of course everything is reversible and no pixels are destroyed.
Anyhow, reverting from the empirical to the principles, I do think it necessary to successfully challenge the correctness of the principles underlying the multi-stage sharpening workflow before accepting that a single pass approach will be SYSTEMATICALLY superior. To do this, there needs to be a combination of both reasons and a highly varied palette of extensive testing of the proposed alternative. I think it is incumbent on the author to do this research and share the results in a manner amenable to systematic evaluation.
There's nothing criminal about the sharpening in the article ... providing that this sharpening is the final sharpening (this is just my opinion, OK?). Since the sharpening is the Capture sharpening (as per Schewe's workflow), it is the first pass before output sharpening. As such it's way too high, IMO. "Snappy and Sharp" applies to the final sharpened image, printed or for web or for whatever medium, not for 'capture' sharpening (again, this is consistent with Schewe's workflow, I believe).
Regarding the empirical principles etc., etc., it seems to me that I have been doing a lot of testing and that I've offered not only examples, but actions for you guys to check out my suggestions . But so far no one has actually given an example testing a one-pass sharpen against a two-pass sharpen and shown that the two-pass is clearly superior, and under what conditions.
And I have certainly not suggested that a one-pass approach is SYSTEMATICALLY superior ... or even that it is superior at all. I personally think, both from tests and from logic, that it will be better in some cases and worse in others. If that is true (which you can check out for yourself if you're interested) then surely that is a useful bit of information? If you knew that for, let's say, images that are upscaled, that you are better off leaving the 'capture sharpening' to after the resize, and that if you did this you would probably have some improvement in the quality of your output, would you not at least consider sharpening after resize rather than before?
Part of the problem with this whole discussion is that some of you seem to think that I am criticizing an established workflow by the gurus of the industry (including Bruce Fraser, who is no longer with us sadly). That may to some extent be the case, but in reality it boils down to 'do you sharpen before or after resizing?'. The reason I say that is that if you sharpen after resizing then it gives you the opportunity (if it is appropriate) to sharpen only once.
Unless the 'before resizing' corrects flaws in the original image (due, for example, to the blurring caused by the anti-aliasing filter) there seems no logical reason to apply it before resizing, and good logical reason to apply it after. In my testing (admittedly limited) I can see no benefit to applying it before. Since almost all of our photos will be resized before output to the web or print, it then follows that if this is true, you are better off resizing and then sharpening.
So let's say that the conclusion is that two types of sharpening are typically beneficial with the current 'sharpening' technology: one with a small radius to 'recover' fine detail, and one with a higher radius, to give the output a boosted impression of sharpness and crispness. I think this may well be so at times. Then, I, personally, would resize, sharpen with a small radius and then sharpen with a higher radius. This does not fit in with the Lightroom model, because Lightroom is strictly 1st phase sharpen, followed by resize, followed by (optional) 2nd phase sharpen.
If you do not sharpen in Lightroom, then, in Photoshop, you can use one-pass sharpen where appropriate, and two-pass sharpen if you think this would be beneficial. There is nothing that I am aware of in PK Sharpen to prevent you from doing this, since it's a Photoshop set of actions.
I would have thought that one of the great benefits of a forum like this one is that it has many very experience members, who could take a suggestion like this one and demonstrate that it is nonsense, or that it is sometimes good, or that it's the best thing since sliced bread (as a home baker I would have to question that analogy
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Robert
