When working in Adobe Photoshop, you’ll likely notice that there isn’t always “a button for that,” meaning, there isn’t always going to be a ready and obvious tool that does exactly what you’d like it to do to solve whatever issue it is you’re up against. Sometimes, you’ll need to get creative with your solutions. Because of this, it’s important to form a solid understanding of what each and every tool does, so when the time comes, you’ll be able to patch two or more together to achieve your mission. Now, this isn’t as bad as it sounds. Tools in Photoshop are grouped logically and after using them for a while, you get the hang of what each does.
In today’s post, I’m going to pretend there are no sharpening filters to be found in Adobe Photoshop. I’m going to come up with a work-around to sharpen the image I’m working on. Since there isn’t an obvious tool at my disposal, I’ll need to think about what other filters do and then work in such a way as to apply one and then customize it to sharpen the image. You’re going to love this post because it’s going to get you to think about working in Photoshop a bit differently than you have before.
Today’s Demo Image
I needed to locate an image that had lots of detail, so any sharpening I did would show clearly. I thought about birds and feathers and decided on a beautiful eagle. Take a look at this.
You can’t beat that when it comes to detail.
The High Pass Filter
Before I begin, I think I need to touch on two different areas of Photoshop. The first is the High Pass filter and the second is the Overlay blend mode, which I’ll discuss down below.
If you aren’t aware of what the High Pass filter does or what it looks like after it’s applied, you’re in for a treat. When this filter is applied to an image, it makes the image look very dull and gray. The reason the image looks so uninteresting after it’s applied it because it removes much of the content of that image.
Basically, this filter removes low frequency information from a signal. In the case of images in Photoshop, this low frequency information comes in the form of smooth areas with little distinction among themselves and other areas around them. The filter does detect and keep areas of specific pixel brightness and color, such as those areas that can be found among edges. The way it detects these edges is to look at sudden differences between brightness and color change. In its true essence, The High Pass filter is a form of a sharpening filter. It detects edges and removes everything from the image besides those edges. Well, it actually kind of removes all the other areas. It turns them gray as you’ll see in my example below. It also brightens the brighter parts of an edge and darkens the darker parts, giving things a “sharper” look.
The Overlay Blend Mode
I’ve talked about blend modes on this website before, but usually in conjunction with one another. Today, I’ll be focusing on one blend mode in particular. That is the Overlay mode. The Overlay blend mode is actually a combination of two other blend modes; Multiply and Screen. These other modes remove white and black respectively, so if you combine these two, you get a mode that removes neutrals, or grays. The Overlay blend mode removes blacks from colors that are lighter than 50% gray and it removes whites from colors that are darker than 50% gray. Essentially, it removes grays, which become transparent. As you may already guessed, a blend mode that removes grays can come in very handy when working with a filter that turns much of an image gray. Everything but sharpened edges.
Sharpening the Image
As you most likely know by now, the very first task that needs taking care of before applying any type of filter is to turn the layer in question into a Smart Object. So that’s what I’ll do right now. I’ll right-click on the layer of the eagle and choose Convert to Smart Object from the menu that appears. From there, I can head up to the Filter > Other > High Pass menu item in the top menu area and click.
After I click that menu item, the High Pass dialog box will appear, that includes only one adjustable setting. It asks how many pixels from an edge you’d like affected by the filter. If you have small images, a smaller number radius would be in order. If your image is larger, such as the one that I’m using is, the radius should be a greater number. In my case, I’ll use a radius of 25.
From the preview, I can see the effect of the filter on the image, both in the dialog and the image itself that sits behind the dialog. When I’m finished with this, I can click the OK button to return to the image in the workspace.
I know what you’re saying right now. You’re saying that the edges look great and that we need to somehow get rid of all that gray. I’d agree with you and tell you to look towards a blending mode to remove the gray.
Do you remember that post I wrote where I talked about what an actual Smart Filter is? In the post, I discussed the separate parts of this type of a filter “shell” is and what those parts are capable of. If you haven’t read this, please do. It’s pretty good.
The reason I bring this previous post up is because I’m going to need to pull out one of those tidbits of knowledge in it to apply a blending mode to the filter itself. The way to do this is to double-click on the Blend Mode button that sits to the right of the filter in the Layers panel.
When I click on that button, the Blending Options dialog will appear, from which I can choose the Overlay option.
After I choose that, I’ll click the OK button and take a look at my results. I’ll enlarge the image so you can see the sharpening of the edges more close up.
Things really are sharper and everything is completely adjustable because I first changed the layer to a Smart Object.
I hope I clearly explained how to sharpen an image using the High Pass filter and the Overlay blend mode in Adobe Photoshop. If you have any questions regarding this post, please let me know in the comment section down below. Thanks for reading!