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Old Dec 3, 2003, 10:38 PM   #1
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Default Unsharp Mask Question

What are the best values for each component? Does it depend on the type of picture? Thanks for any help!
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Old Dec 3, 2003, 11:25 PM   #2
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It depends on the picture and what you want to do with it (print vs. web.) I've been learning some about this myself, here are a few links that might help... they helped me:

http://www.naturephotographers.net/mh1101-1.html

It covers 3 things, the last is USM.

http://www.luminous-landscape.com/tu...ding-usm.shtml

And this thread is a real winner. It looks like it has a post from one of the programmers of USM:
http://www.luminous-landscape.com/cg...=12;t=103;st=9

Eric
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Old Dec 3, 2003, 11:30 PM   #3
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It also depends on which photo editing software you use, as different programs may have different numbered controls.
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Old Dec 4, 2003, 6:17 AM   #4
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I have also found that photos shot in RAW format and converted to TIFF (I convert to 16 bit) are much more sensitive to unsharp mask manipulation than photos shot in high resolution jpeg format.
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Old Dec 4, 2003, 11:33 AM   #5
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Eric’s second link is as well done as I have seen for understanding the settings. Go to the “Local contrast enhancement” link at the bottom. It’s nice to know the official name – I learned it as “defogging”. If you shoot with a non-DSLR digicam and especially if you don’t use a lens hood it seems to help most photos. If you shoot with minimum sharpening you still need to sharpen as it is a contrast enhancement and doesn’t sharpen very much.

I like the recommendations in the first link. I usually start with a radius of 1 for web images and go up to 6 for 30Mb+ images from my film scanner. Conservative is better for sharpening though and his recommendations are probably a better starting point.

I really like a little program called Sharp Control by a guy who posted on the Nikon SLR forum at dpreview who went by Vtie. He quit the forum a few months back because he tired of the constant Canon verses Nikon bickering every time someone wanted to discuss something. He wrote it as part of a technical program he was writing and it does a nice job.

I normally hate it when people link downloads rather than a page you can see what you are getting, but sharp control doesn’t have a page.
Sharp Control: http://www.applied-maths.com/paul/sharpcontrol.zip
Tutorial: http://members.ozemail.com.au/%7Ebin...rpcontrol.html
Some comparisons at the bottom: http://www.digitalworkflows.com/shar...l/workflow.php

He also has a program called PhotoConrol which includes SharpControl – both are free.
Download: http://www.applied-maths.com/paul/PhotoControl.zip
Tutorial: http://members.ozemail.com.au/~binar...tocontrol.html




Quote:
Originally Posted by fporch
I have also found that photos shot in RAW format and converted to TIFF (I convert to 16 bit) are much more sensitive to unsharp mask manipulation than photos shot in high resolution jpeg format.
I can’t argue with your experience but that doesn't mirror my experience. If you normally leave the camera on medium sharpening and extract the raw file unsharpened I could see why the converted raw file might NEED more sharpening, but the converted TIFF shouldn’t be more sensitive to sharpening if the file was converted with the same sharpening you use in the camera.

JPG artifacts are usually enhanced by sharpening and I usually think of files with compression in their history as being more sensitive to sharpening. If you are using a camera like an A1 with superfine JPG that would probably be beyond what most of us could see though.

I’ve shamefully almost given up on 16 bit as it is too much hassle to convert back and forth for the few things Photoshop can do in 16 bit. Maybe the new version will change that for me when I spring for it. But I don’t see any reason 16 bit in itself would be more sensitive to unsharp mask.
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Old Dec 4, 2003, 12:11 PM   #6
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Not having time to read the info on all the links provided, I'll throw out a tip blindly. If using Photoshop, convert the image to LAB mode & then choose the non-colored version. Do all your un-sharp masking on the B&W version & then reconvert back to RGB before saving. This way it only applies sharpening to the edges & doesn't create excessive noise in the colored areas. YMMV
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Old Dec 4, 2003, 1:20 PM   #7
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Ditto to what Kalypso just said.
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Old Dec 4, 2003, 1:37 PM   #8
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I've heard of something similar to what Kalypso & bcoultry are talking about. I heard it as a reference to sharping the mid-tones and not the edges (really dark/light). I've never tried it, but it sounds similar. Switching to LAB and then.... I don't know what and then sharpening.

Photoshop is not one of my strong points.... I'm starting to think I need to take a class in it or something. Something to force me to sit down and actually learn it.

Eric
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Old Dec 4, 2003, 1:51 PM   #9
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Eric...
Photoshop is the Grand Poobah of Poobahs, and yes, whatever it takes to learn it, you really should. I started out with one of those Dummies books because, boy, was I ever dumb. Why don't you give one of them a shot before committing to course time? These books are very good at laying the groundwork, and once you have that, you'll be able to understand all the techniques and variations you come across. Well, that's the theory anyway. I still trip over notions that leave me puzzled to pieces.
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Old Dec 4, 2003, 3:19 PM   #10
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I often use the lightness channel in LAB mode for sharpening. You can get an image looking sharper without looking artificial. SharpControl I am guessing uses something similar along with other stuff. It is pretty sophisticated and I have a hard time beating it with any method in Photoshop.

I find the online tutorials are great anymore for Photoshop. You can start with elementary stuff until you get the nomenclature down and can then search for specifics. I find multi-page tutorials with photos and controls for each step to be more complete than can be shown in a book. One advantage of a book is that you don’t skip anything though.
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