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Understanding the effects of sharpening


show more Understanding the effects of sharpening provides you with in-depth training on Photography. Taught by Deke McClelland as part of the Photoshop CS3 Sharpening Images show less
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Understanding the effects of sharpening

Before I show how sharpening works, I want to give you a sense of what it is. So for those of you in the unlikely event that you've never witnessed sharpening inside Photoshop before, you will now witness sharpening. For those of you who have seen sharpening, which I assume is the vast majority of you, you'll get a sense of why sharpening is there, why we need it, even with a sharply-focused image like this one. This image by the way, is called stunning 12x8.jpeg, its found inside of the 01howitworks folder which itself is found inside the exercise files folder that's available to those of you who are premium members.

It's available for download at the lynda.com Online Training Library. You also have access to this folder if you have the DVD. This image comes to us from photographer Alexandra Alexis of iStockphoto.com, one of my favorites, and we'll see, if I go ahead and zoom this image in a little bit, you'll see that it is impeccably focused and bear in mind, that the purpose of the sharpening filters is to provide the illusion of focus. So why in the world will we apply sharpening filters to an image that's already in great focus. And by great focus, I mean that the portions of the image that are supposed to be in focus are in focus, and those portions that aren't supposed to be in focus aren't in focus.

Notice for example in the case of this model, that her left eye- it's on out right-hand side, but her left eye- is in sharp focus whereas her right eye on left-hand side here is slightly out of focus because its beyond the depth of field and of course the background is very out of focus. Meanwhile, elements like her nostrils and her lips are in sharp focus as well. Now I should mention that there is really nothing we can do about any of this, I can't change the depth of field for example, I can stimulate soft focus in Photoshop, but I cant take something that's out of focus like this background back here for example, and somehow make it miraculously in focus because Photoshop is incapable of generating detail where there is no detail inside the image.

Now I can fix soft focus slightly out of focus items, just a little bit of softness that's either a function of the camera lens or its a function of the scanning element, that kind of thing, but just like focus problems I can fix. Really however, the purpose of the sharpening filters is to preserve the natI've focus of the image by anticipating and reversing even the softening effects of capturing the image, re-sampling it, for example, changing the number of pixels inside the image using the Image Size Command or printing the image.

So lets say for example, in our case we're going to print this image and in printing the image, it's going to get slightly out of focus, it's going to change in terms of its physical size, it's going to get smaller on the page because we're going to print it at a high resolution, and during that translation, either to halftoned dots or to little inkjet marks, we're going to end up with a softer image. So we're going to anticipate that by sharpening it, and I am going to sharpen this image just to keep things simple, I am going to go up to the Filter menu, I am going to choose Sharpen and I am going to choose this guy, Sharpen More.

Normally, I would work with something more sophisticated like Smart Sharpen or Unsharp Mask, but well see those tools later. Right now I am just going to apply the Sharpen More command, and you might be able to see how the image got slightly sharper there. Now our movies get re-sampled down a little bit so you might not see a difference. Lets go ahead and zoom in to the 200% zoom size so you can really see the difference here. I am looking at the sharply-focused eye. This is the before version of the eye and this is the after version of the eye, and you can see that the eye has become tactile almost.

You sometimes hear this kind of over-sharpening effect called brittle or crunchy, and this is definitely a very crunchy image by this point, and it might appear over-sharpened but its actually well-sharpened for output. And Photoshop is able to create the sharpening effect by increasing the contrast of the edges, and well see how that works in the next exercise, but just bear then in mind that's whats going on, its totally an I'llusion, its not actually doing any real sharpening, but it will bring out information that you might not have noticed before.

For example, this is the before version of the nose, this is the after version of the nose which calls attention to all these tiny fine little hairs and the hairs inside the nose as well. So not always good details inside the image. We're also bringing out the wrinkles in the lips, this is the before version of the lips, this is the after version right here, and we have some hairs along the bottom of the lip that we're seeing, we're also calling attention to the hairs along the side of her face, but, you'll notice that the out-of-focus area such as this background here, and to a certain extent this eye are changed dramatically.

So this is the before version of the eye in the background, this is the after version, and the only thing that we are bringing out in the background at this point, I'll go ahead and zoom in here a little bit. The only thing that we're bringing out in the background is the noise, and noise. By noise I mean random variations in pixels, information that wasnt really part of the scene. So this is before, the before version of the background, this is the after version, you can see how the after version is more noisy. So that's something that sharpening brings out as well.

Alright, so there you have it, that's what sharpening looks like, just to give you a sense of what's up, right off the bat here I am going to show you how sharpening works starting in the next exercise.

Understanding the effects of sharpening
Video duration: 5m 26s 10h 36m Intermediate

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Understanding the effects of sharpening provides you with in-depth training on Photography. Taught by Deke McClelland as part of the Photoshop CS3 Sharpening Images

Subject:
Photography
Software:
Photoshop
Author:
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