Photoshop Tutorials: Sharpen Images With The High Pass Filter

Step 3: Apply The "High Pass" Filter To The Duplicate Layer

Now that we have the blend mode set to Overlay, which is going to allow us to see a preview of what we're doing, we can apply the High Pass filter. To do that, go up to the Filter menu at the top of the screen, choose Other down near the bottom, and then choose High Pass. This brings up the High Pass filter dialog box:

Photoshop's High Pass filter is very simple to use. It has a slider bar at the bottom to increase or decrease the intensity of the filter (the "Radius" value), as well as an input box if you'd prefer to type a value directly into it, and that's all there is to it except for the large preview area and the "Preview" checkbox in the top right corner. Definitely much simpler than "Unsharp Mask" or "Smart Sharpen".

To sharpen your image with the High Pass filter, keep an eye on your image in the document window and adjust the Radius value by dragging the slider bar left or right. As you drag towards the right, you'll be adding more sharpening, and as you drag to the left, you'll be reducing the amount of sharpening. You're going to want to start off with a very low radius value, somewhere between 2-5 pixels, and even that may be too much depending on the pixel dimensions of your image. I'm using a small version of the image for this tutorial, and I can already see that 2 pixels is too high. If you go too high, you'll begin to see a halo effect around the edges of your image, and you want to avoid that, so back off on the radius value by dragging the slider bar to the left once the halos begin to appear.

For my image, and again I'm using a small version of the photo for this tutorial, I'm going to set my Radius value to 1.2 pixels, which gives me a nice amount of sharpening around the edges in the image without sharpening any non-edge areas:

Here's my image after sharpening it with a radius value of 1.2 pixels:

If you're working on a larger image, which you probably area if the image came out of your digital camera, you'll most likely end up using a higher radius value, but again, don't go too far. Lower pixel values work best.

There's a couple of things we can do now to fine-tune the sharpening, which we'll look at next.