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12/29/2006 09:45:57 AM · #1 |
I am having a problem getting good results from unsharp mask or smart sharpen with higher resolution images. Everything is fine when I am putting an image on the web and I size it accordingly to say 900 x 600 px. I run sharpen using 85% with a radius of 0.6-0.9 normally, and with a pass or two it looks great. Now the problem is when I have a larger image say 3600 x 2400 px (4 times larger). I know that since there are more pixels the same 85% .6-.9 setting will not yield the same results. So when you have a picture that is larger what setting should you be increasing to see simalar results? I would assume that I would have to increase the radius 4 times for this example? But do I keep my 85% the same?
Also if someone would like to explain threshold that would be great too.
Thanks |
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12/29/2006 09:49:32 AM · #2 |
I increase radius for larger size images. I've tinkered around playing with strength settings, but the same strength setting seems to be good across all sizes for a particular image. Slight increases in radius make the difference. YMMV.
edit: Threshold defines how great a change in contrast must be present for the sharpening effect to apply. Set Threshold to 10, for example, and a white line against a light gray background is not likely to be sharpened. It is useful for keeping the sharpening effect localized to what matters and off of things like skin, blades of grass, etc.
Message edited by author 2006-12-29 09:50:40. |
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12/29/2006 09:53:08 AM · #3 |
And when threshold doesn't quite work to limit the sharpening to what you want (or overly limits it), use the History Brush to paint back the areas that you don't want sharpened. I usually set the history brush to 25% to 50% and smooth out the areas that are too sharp or that show halos.
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12/29/2006 09:54:34 AM · #4 |
| How do you actually use the History Brush? Without fail, every time I try to use it it tells me the Current Image doesn't match the History State or something to that effect. |
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12/29/2006 09:54:47 AM · #5 |
Originally posted by dwterry:
And when threshold doesn't quite work to limit the sharpening to what you want (or overly limits it), use the History Brush to paint back the areas that you don't want sharpened. I usually set the history brush to 25% to 50% and smooth out the areas that are too sharp or that show halos. |
Assuming, of course, that you have a full version of PS and thus a History Brush. Most other programs don't seem to have that feature, so since I don't know what you use, I'll throw that thought in.
EDIT: Oh, and I THINK History Brush is illegal in Basic Editing. I think.
Message edited by author 2006-12-29 09:55:33. |
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12/29/2006 09:55:23 AM · #6 |
Originally posted by dwterry:
And when threshold doesn't quite work to limit the sharpening to what you want (or overly limits it), use the History Brush to paint back the areas that you don't want sharpened. I usually set the history brush to 25% to 50% and smooth out the areas that are too sharp or that show halos. |
Must try that! |
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12/29/2006 09:58:25 AM · #7 |
| Wow crazy fast response time. :) Thanks for the help and I will give that a shot. |
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12/29/2006 10:21:40 AM · #8 |
| Maybe this will in the situation, but, maybe not: 900 increased to 3600 by 600 increased to 2400 is and increase of four times on each side. This is not a four fold increase but a 16 fold increase. (4 X 4 = 16). |
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12/29/2006 10:29:37 AM · #9 |
Another view:
On high-resolution (out of camera) files, a large radius is the last thing you want to use unless there are serious softness issues with the lens used. For sharp originals, use a small radius, about 0.3, and a higher amount, perhaps 200 or even slightly more. Be careful if you're shooting JPEG, because the camera has already applied sharpening. Even if you're shooting RAW and converting with Photoshop's ACR, a small amount of sharpening will be applied as a default, unless you change it.
An alternative to single-pass sharpening is to do two passes at 0.3 radius, both at 150%, and change the blend mode on the second pass to "darken" (edit>fade unsharp mask).
Setting the threshold should be done according to the noise level in the shot, so that noise is not accentuated by the process. Normally, settings in the range of 3 to 10 are required.
If you're shooting with a lens and settings that are producing slightly sofer results, then and only then increase the radius slightly, to 0.4 or 0.5, and reduce the amount. |
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12/29/2006 10:35:16 AM · #10 |
Originally posted by MTR:
Wow crazy fast response time. :) |
I think DPC could probably compete as the fastest response website in the world for photography questions. |
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12/29/2006 10:35:39 AM · #11 |
| Interesting. I apply 300% (roughly) 0.3 radius to images up to about 1280x960 resolution. Above that, 0.3 has radically decreasing effect. At full size, that radius has no noticeable effect at all. I generally increase to 0.6 depending on the makeup of the image. |
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12/29/2006 10:49:13 AM · #12 |
| Well looks like I will have a few things to try now. Is Unsharp Mask still the favorite over Smart Sharpen? |
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12/29/2006 11:01:23 AM · #13 |
Originally posted by routerguy666:
How do you actually use the History Brush? Without fail, every time I try to use it it tells me the Current Image doesn't match the History State or something to that effect. |
You need to set the history state. It's probably illegal because you've cropped the image since the last history state was set (the default history state is set at the point at which you opened the image).
Click the little square to the left of the last history state before you sharpened. That way the only thing the history brush is going to do is undo the sharpening. (you could undo more ... like I may have several passes of sharpening at various levels and I may want to undo all of them, so I set the history state to just before the first of those passes)
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12/29/2006 11:06:46 AM · #14 |
Here's a quick capture showing where I have set the history state prior to using the history brush:
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12/29/2006 11:21:04 AM · #15 |
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