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In this exercise, I'm going to demonstrate the difference between a couple of Remove settings that are available to you inside of the Smart Sharpen dialog box. Those are Gaussian Blur versus Lens Blur, which is why I've created this new demo file that's called Lens vs Gaussian.psd, found inside the 15_sharpen folder. It contains three layers. We're starting off again with the Unsharp Mask layer, the USM layer here, which represents those very unsharp mask settings that we applied a couple of exercises ago. On top of this is the virgin Smart Sharp layer.
So, in other words, I have not applied any sharpening to this layer so far. Then at the very top, we have GBlur diff, because this is that comparison between the unsharp mask settings, and Smart Sharpen set to a Remove value of Gaussian Blur, even though we didn't pay much attention to that. That's what was going on. Now, when you're first seeing these kinds of difference layers, they may be very hard to interpret. There is just a ton of noise going on. It looks like gibberish, it's fairly analogous at first to reading an ultrasound, and trying to figure out what it is you're really seeing, because you have to figure out what's real and what's static.
But as we'll see by the end of this exercise, the difference that we're about to achieve is very different than this difference here. Anyway, I'm going to turn this GBlur diff layer off. Make sure Smart Sharp is turned on and active. Then I'll go up to the Filter menu. Notice the very first command is Smart Sharpen, because that was the last filter I applied. If I go ahead and choose this command or press Ctrl+F, Command+F on the Mac, then I just repeat my last settings, which is not what I want to do. So, I'll press Ctrl+Z, Command+Z on the Mac. What I need to do, if I want to redisplay the dialog box is add the Alt or Option key.
So, Ctrl+Alt+F or Command+Option+F on the Mac displays the last settings for the last used filter which, in this case, are these settings right here. All right, I'm going to go ahead and drag the bug's head down just a little bit. I'm going to zoom in on it. This time I won't use the Zoom tool, because that gets us in trouble, as you may recall from the previous exercise. Instead, I'll just click on the Plus button, which works better inside this dialog box. I'll drag the bug's head down a little bit, so we're viewing it at 200% inside the dialog box, 100% outside the dialog box.
I'll go ahead and scoot this guy over a little bit as well. All right, so notice, we've got Remove, this Remove value which, by default, is Gaussian Blur. You may recall that the Unsharp Mask filter actually uses Gaussian Blur, another filter that's available to us inside Photoshop, in order to achieve a sharpening effect, and so does the Smart Sharpen filter, by default. But you can change that out. You can switch it to Lens Blur or Motion Blur, two other blur filters available to Photoshop. Rather than removing the effects of those filters, which is insanity, because you're not going to apply Gaussian Blur and then try to cover up your tracks after you do it, using one of these settings here.
Instead, you're actually using Gaussian Blur or Lens Blur or Motion Blur to achieve the sharpening effect. But so what? What does that even mean in terms of using these options? Well, here is how it goes. Gaussian Blur is great for accounting for the effects of downsampling. So, if you use the Image Size command in order to decrease the size of an image for the web, for example. You're using Bicubic Interpolation, which is the default setting, why then you might want to follow up with little bit of Gaussian Blur style smart sharpening here, a very low amount setting, 100% or less, and a very tiny radius setting, something like 0.3, 0.4, 0.5, something along those lines.
Also, Gaussian Blur is great for sharpening scanned images. So, if you start with a nicely focused image and you scan it, and it suffers from just a little bit of softness, whether because of the thickness of the glass or some other blur variable that's going on, why then Gaussian Blur can help to get rid of that. If you're trying to sharpen a digital photograph, I urge you to move on to Lens Blur, which gives you much better edges as we're about to see. Now, it's a subtle difference, but it's a meaningful difference.
Then Motion Blur is designed to correct for the effects of camera shake, and I'll show you what that means later. For now, I want you to go ahead and choose Lens Blur, because this is a digital photograph after all. Now, did you notice that difference? By the way, I want you to watch this preview right here. Watch the halo inside of this proboscis or whatever it is. I'm going to switch between Gaussian Blur. Notice how thick that light halo is. Then I'll switch over to Lens Blur. It gets a little thinner; actually, it gets quite a bit thinner, even though the Radius value did not change at all.
Well, what you need to do, if you want to keep your Radius value about the same, is you need to increase it by half again. So, I'm going to take this value up to 4.5. So, it was 3 before, half of 3 is 1.5. I add 1.5 to 3, I get 4.5. So, I'm going with 4.5 pixels, I'm going to leave More Accurate turned off. We'll discuss that shortly. So, 500%, 4.5, Lens Blur, let's see what that looks like. Go ahead and click OK in order to apply that setting. Now let's run through those same steps we did before. Go up to the Edit menu, because we still have all sorts of strangely colored halos.
Choose Fade Smart Sharpen; Ctrl+Shift+F, Command+Shift+F on the Mac. Notice how close that keyboard shortcut is to the filter shortcuts. So, it's Ctrl+Alt+F or Command+Option+F to redisplay the dialog box. It's Ctrl+Shift+F or Command+Shift+F in order to fade the effects of that filter. Even though the Fade command is applicable to all sorts of things, brush strokes, any pixel level edit, it does have a keyboard shortcut that's very much analogous to filtering. All right, anyway, I'm going to go ahead and choose that command.
Notice all the weird colors that are going on inside this butterfly head. I'm going to go ahead and zoom in on it, and move it over a little bit, so that you can see all of those weird blues and purples. They drop out as soon as I choose Luminosity. They all go away. Notice how everything settles down there. Then I'm going to reduce my Opacity level to 30%. Once again, I'm just running through those same steps as before. I could've applied a lower amount value in the first place. I really want you to see the sharpening at work onscreen here. I'll go ahead and click OK, and now let's find the difference.
So, with Smart Sharp selected, I'll switch the Blend mode from Normal to Difference, like so. That produces what appears to be a black background. I'll go ahead and press the Escape key here on the PC to make sure the Blend mode option is no longer active. Then I'll press Ctrl+Shift+Alt+E or Command+Shift+Option+E on the Mac, in order to create a merged version of those two layers blended together. I'll call this guy LBlur vs GBlur , like so. Then I will press Ctrl+L or Command+L on the Mac, in order to bring up the Levels dialog box.
You know what I ought to do. I'm going to cancel out of there. I should show you how to bring up the last used Levels setting from the keyboard; you can press Ctrl+Alt+L or Command+Option+L on the Mac. Just by virtue of the fact we added Alt or Option, so the same thing we did with the filter, right? We bring up the last applied settings here. So, notice that I've changed the white point value to 2. Click OK. You may look at this and think golly! I have no idea of what I'm looking at. It looks like a bunch of that same static we saw before.
Let's compare these two difference layers together. This is the one we saw last on. This is the difference between the two GBlur settings. So, notice that we're seeing a lot of noise going on and a lot of difference between the noise. So, in other words, the Unsharp Mask version of the butterfly had less noise than the Smart Sharpen version. That's why we're seeing all these noise differences, but if I turn that layer off, I want you to see something. Around the edges, notice these edges look fairly routine. The edges are kind of black, maybe a little bit white here and there.
However, as soon as I turn off the GBlur diff, I see these big, thick outlines around the edges. So, there's all sorts of molten detail around those edges. That's because the edges are fundamentally different. So, it's not just the noise, which we are seeing all over the place here, but it's also a difference between the edges, and the edges you get from Lens Blur are better. They are sounder edges. All right, so I'm going to go ahead and turn off this Difference layer. Let's go ahead and switch back to Smart Sharpen.
Let's change its Blend mode back to Normal, because Difference has served its purpose here. Let's go ahead and zoom in, so that we can see the difference between these two sharpened images. This is the Smart Sharpen version of the image, set to Lens Blur, and this is the Unsharp Mask version of the image, which employs Gaussian Blur. Now, you may look at those two things and say, I didn't see any difference. All right, here's what I want you to look at. Watch this area inside of the curling proboscis. This highlight right here, notice how thin and fragile the highlight is in the Unsharp Mask example.
As soon as I turn on Smart Sharpen, it grows a little brighter, a little more information held inside of that area. So, that's the kind of effect you're going to get using Lens Blur. You're going to get sharper details; you're going to get better details out of your image. Bear in mind, this is a fairly low-resolution image. Anything you see work inside of a low-res image, is going to work even better inside of your high-resolution original digital photographs. In the next exercise, I will demonstrate how to work with the More Accurate check box.
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