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03/26/2011 03:04:52 PM · #1 |
| Hey guys, gots a question for you. I have always used the Unsharpen mask in either GIMP or Capture NX. During the bird in flight challenge, I noticed that while sharpening, many of my shots developed grain in the sky. The image is sharp to begin with, so I don't feel like I'm oversharpening, just maybe doing it wrong...I have seen this before on certain images and just wanted to ask. What is the best way to sharpen an image? Is there a proper sharpening technique that I'm missing??? I've always just adjusted the sliders until it looked good, but now I'm curious, in general, is there a technique that perhaps I'm not aware of. I did a search, but couldn't find the answer, even though I know I saw a thread on this not too long ago. Anyway, any and all help appreciated, thanks again. |
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03/26/2011 03:19:18 PM · #2 |
Almost surely the grain/noise was there to begin with, and was accentuated by the USM filter. Try using noise-reduction on the image and then sharpening again using the same settings and see if there's a difference.
I often find running the USM filter at a "lower" setting two times will give a better result than a single pass at the higher setting. I also never sharpen until I'm at the final-sized image. For an entry-sized image my typical settings ar (Photoshop terms) Amt: 66-88%/Dia: 0.6-1.3 pixels/TH = 5.
I also use a "high-radius" USM to improve contrast in a lot of images, with settings around 15%/Dia: 50 pixels/TH = 0. |
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03/26/2011 03:20:11 PM · #3 |
There is no one right way to sharpen with USM.
If you are getting 'grain' in the sky, you are oversharpening the noise there. Increase your threshold a bit to reduce the sky from sharpening.
This is a basic primer in using USM: //www.scantips.com/simple6.html
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03/26/2011 03:20:34 PM · #4 |
You might want to increase the clipping setting of your unsharp mask(I don't know what it is called in your software, but thats what Paintshop pro calls is.) This tell the adjustment how far apart the adjacent pixels need to be for them to be sharpened. The higher the clipping number, the stronger the contrast must be between adjacent areas for sharpening to kick in. The idea is that you want to sharpen the edges, but not solid or smoothly graduated areas. If you increase your clipping, then very close tones, such as blue in a sky will ideally not be sharpened. I usually sharpen at a clipping of 3 or 4, but occasionally increase it to 5.
If the image is for an advanced editing challenge, I will often duplicate the layer, sharpen and then mask through so that I've selectively sharpened only the desired areas.
Message edited by author 2011-03-26 15:21:58.
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03/26/2011 03:33:52 PM · #5 |
Originally posted by Yo_Spiff:
You might want to increase the clipping setting of your unsharp mask(I don't know what it is called in your software, but thats what Paintshop pro calls is.) This tell the adjustment how far apart the adjacent pixels need to be for them to be sharpened. The higher the clipping number, the stronger the contrast must be between adjacent areas for sharpening to kick in. The idea is that you want to sharpen the edges, but not solid or smoothly graduated areas. If you increase your clipping, then very close tones, such as blue in a sky will ideally not be sharpened. I usually sharpen at a clipping of 3 or 4, but occasionally increase it to 5. |
In Photoshop this is the Threshold (TH) setting; it works the same as you describe. |
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03/26/2011 03:43:05 PM · #6 |
| Awesome guys!!! There is some great info here... Spiff, I've yet to really sit down and learn how to do masking in GIMP... That's what I'm going to tackle next, I just figured out how to dodge and burn..lol... so I've got a ways to go... |
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03/26/2011 04:25:32 PM · #7 |
I can't remember if Gimp allows you to fade the mask, but fading the light channel in your USM and increasing the threshold will go a long way to getting rid of the sky noise.
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03/26/2011 04:39:51 PM · #8 |
Just thought I'd throw this in for the Canon users.
The latest version of DPP (3.9 I think) has a few upgrades
5 star ratings
USM sharpening
Can now straighten the image when cropping
All the latest lens correction information
If you have taken 6 images with the same settings you can highlight all six and take them into be edited.
You can edit just one but then copy what you did to a clipboard and paste it to all of them but then you can tweek each one individually a bit more if desired.
Seeing I use CS3 I cannot edit in raw with that program so I am now using Canon's DPP
The more I play with it for RAW images I'm actually finding it very good
I think I will make it a part of my workflow instead of upgrading photoshop
Message edited by author 2011-03-26 16:40:59. |
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03/26/2011 07:45:04 PM · #9 |
Originally posted by RamblinR:
Just thought I'd throw this in for the Canon users.
The latest version of DPP (3.9 I think) has a few upgrades
5 star ratings
USM sharpening
Can now straighten the image when cropping
All the latest lens correction information
If you have taken 6 images with the same settings you can highlight all six and take them into be edited.
You can edit just one but then copy what you did to a clipboard and paste it to all of them but then you can tweek each one individually a bit more if desired.
Seeing I use CS3 I cannot edit in raw with that program so I am now using Canon's DPP
The more I play with it for RAW images I'm actually finding it very good
I think I will make it a part of my workflow instead of upgrading photoshop |
I agree. You and I posted in the forum when I posted about the upgrade to DPP. I think it's much better than it was in the past, and I've been using it A LOT for my RAW files lately. I find it gives you just the right about of control in getting the initial RAW file ready for more stylization in programs like Photoshop etc. Very happy with where Canon took this software. |
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03/26/2011 07:47:51 PM · #10 |
I agree with others here on the USM settings and techniques. Steve (Yo_Spiff) beat me to it, but I was also going to mention that masking for selective sharpening was also an option (Advanced Editing) and a powerful means of bringing attention to certain areas of the photo relative to others.
Also, you might consider doing High Pass sharpening instead. In Photoshop you duplicate the layer, desaturate the top layer you just created using the "Control+Shift U" keys (Command+Shift U for Macs), then go to filters/other/high pass and adjust until you have good edge definition without over doing it to prevent halos. Click OK, and then set that top layer to either Overlay or Soft Overlay. Turn the layer "eyeball" on or off to see the difference. If it's a little heavy handed you can easily adjust the layer opacity down to your liking. If it's not enough then you delete that top layer you just created and repeat the process as you can reduce the effect with opacity sliders, but you can not increase. Again, this is only legal in Advanced or Expert editing because you are creating a second layer with pixel data.
Dave
Message edited by author 2011-03-26 19:54:13. |
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03/26/2011 09:10:41 PM · #11 |
Originally posted by DCNUTTER:
Also, you might consider doing High Pass sharpening instead. In Photoshop you duplicate the layer, desaturate the top layer you just created using the "Control+Shift U" keys (Command+Shift U for Macs), then go to filters/other/high pass and adjust until you have good edge definition without over doing it to prevent halos. |
You don't need to desaturate; High Pass does that automatically when you invoke it.
R. |
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03/26/2011 10:29:22 PM · #12 |
Originally posted by Bear_Music:
Originally posted by DCNUTTER:
Also, you might consider doing High Pass sharpening instead. In Photoshop you duplicate the layer, desaturate the top layer you just created using the "Control+Shift U" keys (Command+Shift U for Macs), then go to filters/other/high pass and adjust until you have good edge definition without over doing it to prevent halos. |
You don't need to desaturate; High Pass does that automatically when you invoke it.
R. |
The High Pass filter does indeed give you a grey scale image in the viewer, but the color information is still present. The higher you go with the radius setting you will start to get color induced into your preview and those colors will start to shift or fringe from the original color in your photo. It will easily be apparent once you overlay the effect onto the bottom layer. When using an actual desaturated layer before invoking the high pass you will only be effecting the contrast in luminosity. When overlaid you can see noticeable differences between the two methods.
The color shifting and fringing will be more obvious when higher radius values are used, but just because you don't see it in the preview when using lower values doesn't mean it's not at the very least subtly effecting areas of the photo when applied. A lot of people who skip the initial desaturation layer step and go straight to the high pass filter normally include the same process after the fact by keeping the high passed layer selected and then applying a destructive (from the menu) Hue/Sat desaturation effect before changing the blending mode.
The easiest way to test this is to take one image into Photoshop and apply the method I described for one layer. Then click on the "eyeball" of that layer to disable it and make a second layer onto of the original and apply the high pass filter without desaturation. Make sure to use exaggerated levels (higher than needed for the image) to really see how it effects color. Then toggle the eyeballs of the layers on and off back and forth to compare the results. When I do this I see obvious color shifts around edges etc.
Dave
Message edited by author 2011-03-26 22:31:52. |
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03/26/2011 11:13:25 PM · #13 |
Originally posted by DCNUTTER:
The easiest way to test this is to take one image into Photoshop and apply the method I described for one layer. Then click on the "eyeball" of that layer to disable it and make a second layer onto of the original and apply the high pass filter without desaturation. Make sure to use exaggerated levels (higher than needed for the image) to really see how it effects color. Then toggle the eyeballs of the layers on and off back and forth to compare the results. When I do this I see obvious color shifts around edges etc.
Dave |
I've seen the effect before when noodling around, yes, but only noticeably when the levels are so exaggerated as to be useless. That's interesting information, that it may be subtly degrading the image at lower levels. This suggests to me that the best way to use High Pass might be on the luminance layer in Lab Color...
R. |
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03/26/2011 11:20:30 PM · #14 |
Originally posted by Bear_Music:
Originally posted by DCNUTTER:
The easiest way to test this is to take one image into Photoshop and apply the method I described for one layer. Then click on the "eyeball" of that layer to disable it and make a second layer onto of the original and apply the high pass filter without desaturation. Make sure to use exaggerated levels (higher than needed for the image) to really see how it effects color. Then toggle the eyeballs of the layers on and off back and forth to compare the results. When I do this I see obvious color shifts around edges etc.
Dave |
I've seen the effect before when noodling around, yes, but only noticeably when the levels are so exaggerated as to be useless. That's interesting information, that it may be subtly degrading the image at lower levels. This suggests to me that the best way to use High Pass might be on the luminance layer in Lab Color...
R. |
I totally agree. Many benefits of using Lab color. I love having the luminance layer isolated. I'll have to experiment with that as well...high pass on the luminance layer. I do use Lab for other things when I feel the need such as altering saturation levels without banding and other artifacts. Worth looking into...that's for sure.
Dave |
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03/26/2011 11:25:55 PM · #15 |
Originally posted by DCNUTTER:
I totally agree. Many benefits of using Lab color. I love having the luminance layer isolated. I'll have to experiment with that as well...high pass on the luminance layer. I do use Lab for other things when I feel the need such as altering saturation levels without banding and other artifacts. Worth looking into...that's for sure.
Dave |
Make it so: I task you to return with a report, sir!
R. |
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03/26/2011 11:37:07 PM · #16 |
Originally posted by Bear_Music:
Originally posted by DCNUTTER:
I totally agree. Many benefits of using Lab color. I love having the luminance layer isolated. I'll have to experiment with that as well...high pass on the luminance layer. I do use Lab for other things when I feel the need such as altering saturation levels without banding and other artifacts. Worth looking into...that's for sure.
Dave |
Make it so: I task you to return with a report, sir!
R. |
LOL...will do. :) |
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