How To 

How To Use Photoshop’s “High Pass” Filter To Sharpen An Image

When an image is a little fuzzy, sharpening is the best way to highlight details and bring an overall clarity to the piece. While you can achieve this by manipulating levels or simply fiddling with the “Sharpness” settings, you can risk over-sharpening areas that are contextually irrelevant to the picture as a whole. To avoid this, the “High Pass’ filter might be your best option.

1. Duplicate the image layer.
We’ll start by creating a new image layer to apply the filter to. To do this, either right click the desired layer and select “Duplicate Layer…” or hit Cmd+D (Ctrl+D for Windows) while the appropriate layer is selected.

2. Open the “High Pass” filter.
With the duped layer created and on top of the original in the Layers panel, hit “Filter > Other > High Pass..” to open the High Pass filter’s window.

3. Adjust the “High Pass” filer.
You’ll notice that this filter will turn the entire image gray - this is what we want. We’ll negate the gray area with a blend mode once the appropriate shadow and light values are enhanced. To do this, adjust the “Radius” slider until just the desired details within this picture are highlighted. For this exercise, we want to augment the values native to the kitten’s fur and eyes. By checking the “Preview” option, we’re able to see how these changes apply to the image as a whole. Otherwise, we can drag and zoom in / out of the preview space to see how the filter affects specific details. Once we’re satisfied with the results, we’ll click “OK”.

4. Apply a blend mode.
We’ll now combine the filtered image and the original through an appropriate blend mode. A few of these work well with negating the negative gray space created by the high pass filter - specifically those located under the “Overlay” option. For this image, the “Soft Light” mode fits the best.