Join Deke McClelland for an in-depth discussion in this video Traditional High Pass sharpening, part of Photoshop CS5 One-on-One: Mastery.
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In these next couple of exercises we're going to take a look at the Smart Filter approach to High Pass Sharpening. If you recall back in Chapter 15, High Pass Sharpening is very useful in combination with low-frequency images, in particular portrait shots, because it does a great job of avoiding clipping. However, if you're going to apply High Pass using Smart Filters, then you have to jump through a few hoops that you don't normally have to jump through. So I'm going to review how you do it the static way and then we'll compare that to the Smart Filter way and you can decide which approach you prefer.
I've saved the results of the previous exercise as Smart squirrels.psd. I'm going to switch back for a moment to Rodents in love.jpg which is the original image that thus far has not been sharpened and we're going to sharpen it using High Pass. Here's what you do. You press Ctrl+Alt+J, Command+Option+J on a Mac to jump the layer, and then go ahead and call it High Pass and click OK. Then you go up to the Filter menu, you choose Other, and you choose High Pass or if you loaded dekeKeys, you can press Shift+F10. Now, the High Pass Radius works differently than the Smart Sharpen Radius when Smart Sharpen is set to Lens Blur, because High Pass works with Gaussian Blur.
So that's two fundamentally different approaches where Radius is concerned. As a result, even though we use 3.5 pixels of Radius in the previous exercise, we're going to take that number down to 2.5 pixels of Radius because you only need about 67% as much Radius when you're working with High Pass. Anyway, I'm going to go ahead and click OK to accept that modification and I'm going to zoom-in on my image. Now, you can see it generally makes the image gray; it just leaves the edges more or less intact. So we're seeing some of the highlights, some of the shadows around the edge details and where there are no edges, the details are going to gray.
However, they're not quite altogether going to gray, I wish they were, but we still have some color artifacting going on. So I'm going to get rid of those colors the nondestructive way using an Adjustment layer by pressing the Alt key or the Option key on the Mac and clicking this Black/White icon at the bottom of the Layers panel, and then I'll choose the Hue/Saturation command and I'm going to call this guy desaturate and I'll turn on Use Previous layer to Create Clipping Mask because we only want to desaturate the High Pass layer and nothing more. Click OK and then reduce the Saturation value to -100 and those slight colors that we were seeing in the squirrel's eye there and in its fur go away.
So just to give you a sense of what we've done, because it's pretty subtle, I'll zoom-in here. This is without that desaturation layer. See those little bits of color in the eye and quite a bit of green and weird colors elsewhere going on here inside the fur, a little bit of red along this whisker, and then when we turn Desaturate back on, all those colors go away. Then you click on High Pass and you switch over to one of your contrast modes. So at the very least you would choose Overlay in most cases. If you want a stronger effect, you would go to Hard Light, and if you want a stronger effect still, go to Linear Light.
I'm going to crank this all the way up to Linear Light. We get this effect right here. But if we didn't have Desaturate, if I turn that off for a moment, notice how we have all these aberrant colors showing up inside the squirrel's fur very much like those aberrant colors that were associated with the Smart Sharpen Filter. The difference is Smart Sharpen you set to luminosity, and so you go ahead and drop out the colors that way. There is no combo luminosity Linear Light function. There is no blend mode that combines those two together.
So we have to desaturate in a separate operation by creating this desaturate layer and the reason I'm running you through this whole scenario here is because we don't have the option of desaturating a High Pass effect when we're working with Smart Filters. Now, the other thing we should do just so that we're comparing apples to apples here is we should go ahead and load that Filter Mask. Recall back in the previous exercise that I created this Filter Mask, so that we are only sharpening specific details inside of the squirrels.
I want to load that Filter Mask inside of my composition at hand, so I need to make sure I have both of these images open; that is if you're working along with me, you want Smart squirrels.psd as well as your Rodents in love.jpg file. I'll switch back to Rodents in love, I'll zoom-out at least to let's say the 66.7% zoom ratio. I'll make sure my High Pass layer is active; then I'll go up to the Select menu, choose Load Selection and here inside the Load Selection dialog box, you want to switch Document to Smart squirrels.psd. That's why it's essential that it's open, otherwise you won't see it.
Then you don't want the squirrels Transparency because the squirrels layer is a big rectangle, so there is no Transparency associated with it. What you want instead is the squirrels Filter Mask, which you can grab which is great actually. You don't want to invert it, you want a New Selection, you click OK, and then there's your selection outline which represents that exact same information that's associated with the Filter Mask. Now you convert it to a layer mask for the High Pass layer by clicking on the Layer Mask icon down here at the bottom of the Layers panel, and we have an analogous effect now.
Now what I want to do is show you how to get the same effect using Smart Filters as I will do in the next exercise.
Recommended prerequisites: Photoshop CS5 One-on-One: Fundamentals and Photoshop CS5 One-on-One: Advanced.
- Using masks and blend modes in radically new ways
- Mastering the Pen tool and Paths panel
- Transforming and maximizing Smart Objects
- Employing Smart Filters to create complex effects
- Exploring the capabilities of Bristle brushes and the Mixer Brush
- Merging multiple images into seamless panoramas
- Exploring the full range of luminance with HDR Pro
- Recording actions and batching-processing images