High Pass Filter

The high pass filter is a simple action you can run, where Photoshop will complete a series of steps applying a high pass filter to your image.

High Pass filter basically finds the edges of parts of your image (things like eyes, fur, etc) and when coupled with a blend mode that adds contrast, accentuates those edges. The good thing about the high pass filter is that is is a way to sharpen the image without being destructive. It doesn’t add noise because it isn’t sharpening the pixels, but rather defining the edges of parts of your image.

This therefore works best if there are some edges for it to “see”. If you have a very black, dark, under-exposed dog with dark eyes, and it is significantly out of focus, it will have no edges to pick up on, and probably won’t do a very good job.

It can therefore work too well on images with defined “edges” (like Loki’s bright eyes against his dark fur) and you will definitely want to lower the opacity on the layer quite a lot so that the eyes don’t end up glowing and being out of control.

I recommend lowering the opacity to at least 50% in most cases anyway. This filter is strong and the eyes can very quickly look over-sharpened and over-worked.

To install & use the action:

  • Download it to your computer
  • Unzip it (or just download the .atn file)
  • Drag and drop the file into Photoshop.
  • Go into Photoshop to the photo you want to sharpen.
    • Be on a layer with the dog. If you’ve messed around with the background, you need to be on the layer with the subject. 
    • If the layer already has a layer mask, either create a duplicate layer and remove the layer mask, or choose a different layer without mask. 
  •  Open the Actions menu (it looks like a play button) if you have it on your workspace. Otherwise, go to Window > Actions
  • Find the High Pass Eyes folder. Click it. 
  • Click “> High Pass Eyes”
  • Click the play button at the bottom of the Actions window.
  • Photoshop will run a series of steps including creating a new grey layer.
    • Move this so it’s above your subject layer if it isn’t already.
  • Mask in the areas you want to be sharpened
  • Lower opacity as required.