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Author Topic: Fractal Sharpening.. try it  (Read 3720 times)
Ray
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« on: September 20, 2005, 01:11:02 AM »
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This is another thread that has disappeared. I'll recap the gist of it. Paul suggested that GF 4 could enhance sharpening properties. Jonathan suggested Focus Magic was a better deal.

I've tried both. I bought GF a few years ago, partly because Michael R. recommended it and partly because I'd read of this fascinating theory of 'fractals' which describes a similarity of structure in the small and the large. (Ie. a tree trunk and branches has a similar structure to a branch and smaller offshoots, which in turn has a similar structure to the veins in a leaf. Find the recurring structure and you can do marvels.)

It sounds great in theory and the name'Genuine Fractals' leads one to believe this is an implementation of the theory. Maybe it is, to some degree. How would I know? All I can do is look at the results, and when I do, I get a sense that I'm looking at very, very marginal improvements. Differences between GF and PS bicubic are of the highest order of pixel peeping. They are there, of course, at 400% magnification on the monitor. Or, if one takes a low resolution image or a small crop, interpolates it with GF, sharpens it in PS, repeats the process a couple of times, one can end up with a fair representation of an impressionist art work, which might be quite interesting. One could add this process to the 'artistic filters' section, along with poster edges and pallette knife.

Focus magic does a similarly botched job, but at small print sizes (8x12" and perhaps larger) the images really do look sharper. Do a bit of pixel peeping, however, and the enlarged crops look just awful; black dots, black lines and misshapen forms. However, one thing in favour of Focus Magic, it appears to be able to create an 'impression' of greater sharpness without the increase in grain and color noise that the normal 'unsharp mask' produces.

For this reason I tend to favour it in preference to GF as regards sharpening methods.

As a general comment, we seem to be scraping the bottom of the barrel with regard to sharpening programs. As far as I can see, there are no breakthroughs yet.
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Mark D Segal
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« Reply #1 on: September 20, 2005, 06:53:38 AM »
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As a general comment, we seem to be scraping the bottom of the barrel with regard to sharpening programs. As far as I can see, there are no breakthroughs yet.
Yes there is - PK Sharpener Pro - which Michael has reviewed on this website. Check it out. If you can't solve a sharpening problem with the choice of options and implementation flexibility that program gives you, the problem most likely is not solvable.
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Mark D Segal (formerly MarkDS)
Author: "Scanning Workflows with SilverFast 8....." http://www.luminous-landscape.com/reviews/film/scanning_workflows_with_silverfast_8.shtml
Ray
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« Reply #2 on: September 21, 2005, 01:38:44 AM »
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Mark,
Checking out PhotoKit Sharpener is another thing on my list of things to do. I've been a bit dubious about the entire process of spending lots of time to acheive marginal improvements at the pixel level. I guess I find Focus Magic interesting because it's dead simple to use and produces a sharpening effect without intoducing additional grain. In fact, it can even remove remnants of noise left over from the Neat Image process.
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Mark D Segal
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« Reply #3 on: September 21, 2005, 07:25:15 AM »
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Ray, without intruding on something as personal as your list of priorities - because we all have them - in fact right now I should have my car in the repair shop looking at the muffler, but here I am dialoguing on L-L. Anyhow - back to the priorities - let me recommend that you move testing PK Sharpener Pro a notch or two higher. It is a very easy program to use "out of the box", and like everything takes some experimentation to learn to use well; but this is rewarding. The amount of work normally ranges between one and three automated actions that happen quickly, at the beginning, part way through processing and then just before printing. Read Michael's review of this software and you'll get a good idea, but better still download it and try it. PK Sharpener does not add grain, but you would want to do your grain reduction before sharpening, because there is no point sharpening the grain you would prefer to get rid of in the first place. The Capture Sharpeners (for film) have a smoothing layer, which has a default opacity of 33%. When you pump the image to 50% magnification on your monitor (to avoid aliasing) you'll get a clear idea of whether to reduce or increase the smoothing effect (anyhow quite subtle). Since each PK effect is contained on layers with masks, it is non-destructive and allows you to manage sharpening effects either globally, or with a paint brush - selectively.
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Mark D Segal (formerly MarkDS)
Author: "Scanning Workflows with SilverFast 8....." http://www.luminous-landscape.com/reviews/film/scanning_workflows_with_silverfast_8.shtml
francois
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« Reply #4 on: September 21, 2005, 07:46:53 AM »
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...let me recommend that you move testing PK Sharpener Pro a notch or two higher. It is a very easy program to use "out of the box", and like everything takes some experimentation to learn to use well; but this is rewarding. The amount of work normally ranges between one and three automated actions that happen quickly, at the beginning, part way through processing and then just before printing. Read Michael's review of this software and you'll get a good idea, but better still download it and try it. PK Sharpener does not add grain, but you would want to do your grain reduction before sharpening, because there is no point sharpening the grain you would prefer to get rid of in the first place. The Capture Sharpeners (for film) have a smoothing layer, which has a default opacity of 33%. When you pump the image to 50% magnification on your monitor (to avoid aliasing) you'll get a clear idea of whether to reduce or increase the smoothing effect (anyhow quite subtle). Since each PK effect is contained on layers with masks, it is non-destructive and allows you to manage sharpening effects either globally, or with a paint brush - selectively.
Also, support on PixelGenius forums is very good, with Bruce Fraser and Jeff Schewe giving useful info on PKS.

francois
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Francois
Ray
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« Reply #5 on: September 21, 2005, 08:11:40 PM »
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in fact right now I should have my car in the repair shop looking at the muffler, but here I am dialoguing on L-L.
And I should have taken my car in for its 15,000Km sevice a few thousand KMs ago, but what the heck  Cheesy .

I did of course read Michael's review of PK Sharpener when it first appeared, before it had 16 bit capability, and I have occasionally tried out a few dedicated sharpening programs, such as Focal Blade, but was never particularly impressed. I always got the impression the sharpening results were good because they weren't aggressive and that one could get similar results in PS with non-aggressive use of the USM. I also get the impression such programs might lend themselves better to a work-flow situation when processing hundreds of similar images, which is not my situation.

At present I'm in scanning mood and am wondering what the best approach is to sharpen images I took in my inexperienced youth when I didn't have the option of changing film speeds without loading a new roll of film. When faced with the option of 1/30th at f8 or 1/60th at f5.6, with a 50mm lens, without tripod, I generally opted for 1/30th at f8, if it was a landscape.

I'm rather intrigued by Focus Magic's rendering of such shots. At magnifications greater than the eye would see, even when pressing one's nose to a print, there appears to be a sprinkling of small, black dots and short, thin black lines which really do give the impression of an image that's more in focus.

I have just recently download the trial version of Photokit Sharpener and first impression are, it does a better job than Focus Magic with images that are already quite sharp. But Focus Magic appears to have the edge (pun intended) with a noticeably blurry or slightly OOF shot, which is not surprising because that's what it was designed for. But those are just first impressions. The comparison process is rather slow because Focus Magic really is very slow, an indication of the intense computation that must be taking place.
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Mark D Segal
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« Reply #6 on: September 21, 2005, 10:37:46 PM »
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Ray,

In my experience - and I know others share it - out of focus photographs cannot be brought into focus with sharpening, because as you know, sharpening deals with acutance, not circles of confusion. That much said, in PK Sharpener's "Creative Sharpener" there is a tool called DOF Sharpener 3. Using it comes as close as one can get to simulating improved focus.
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Mark D Segal (formerly MarkDS)
Author: "Scanning Workflows with SilverFast 8....." http://www.luminous-landscape.com/reviews/film/scanning_workflows_with_silverfast_8.shtml
francois
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« Reply #7 on: September 22, 2005, 02:13:13 AM »
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....That much said, in PK Sharpener's "Creative Sharpener" there is a tool called DOF Sharpener 3. Using it comes as close as one can get to simulating improved focus.
Some other tools in PKS can also save a unsharp photos. Edge sharpen and Super Sharpener are very powerful but they must be used very carefully and with a mask. They can also easily destroy an image. I've been able to print 75cmx50cm (30x20) posters for a friend from two slightly blurred 4MP D2H photos. The posters were acceptably sharp considering the initial photos (JPEG, 4MP, slightly unsharp).

francois
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Francois
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