Bite-Size PS Tutorials: Sharpening with High Pass Filter

Two things converged for me recently: an increase in questions sent to me regarding my commercial photography and the unexpected popularity of my bite-sized Photoshop tutorials. Both occurrences are born from the same inquiry of understanding how certain things are achieved. I used to bother people constantly with questions on how I could attain a certain look in post-processing, or how an image is so sharp, and so on. From time to time, I still do. So, I'm going to do my best to make the answers to the most common questions readily available with this mini series.

I'll start with my usual caveat. This collection of brief tutorials are not for you veterans photographers and retouchers. With that in mind, here is a quick round-up of the tutorials in this series so far:

• How to quickly create your own Photoshop actions to speed up workflow.
• How to "crush the blacks" as seen in cinematography and why it's useful to do.
• How to create even colors throughout your images for that polished, commercial look.

Why Sharpen with the High Pass Filter?

In my early days of photography, I'd look at my images, then at a top photographer's infinitely sharper images and I would misjudge the reason for the chasm. As a result, I would stand on the clarity slider in Lightroom until it screamed out in distress, followed by some sharpening through Photoshop to finish it off. Once I realized that Spinal Tap's advice on amps isn't pertinent to sharpening, I dialed it right back. But the truth is, sharpening in post is important and because it can be done in a number of different ways, some thought ought to be put in to which method you use.

When I'm looking for the optimum technique in any form of post-processing my images, I'll see what the top retouchers use. I've mentioned this before in my tutorials but this group of e-artists are excellent for sniffing out the best way to squeeze out quality from an image and although the ones I've spoken to sometimes use more than one technique, the High Pass filter is their go-to. There are a number of reasons for this but the chief motivation for most is that a High Pass filter will be a separate layer and not interacting directly with the pixels of your image. This is often referred to as a "non-destructive" form of editing.

One important thing to always remember about sharpening is that contrary to what the methods are called, sharp images are made in camera, not in Photoshop. All you're doing it bringing out the details that are already there and you should be doing so subtly.

How to Sharpen with the High Pass Filter

Firstly, I'm going to provide a step-by-step text tutorial as it's easier to navigate should you miss a step:

1. Create a stamp visible layer of your image so far using Shift+Ctrl+Alt+E on Windows or Shift+Command+Option+E on Mac.
2. Control+J/Command+J to duplicate the stamp visible layer.
3. Navigate to the top menu Filter > Other > High Pass
4. Enter the value 3.5 pixels (This is trial and error but 3.5 is by far my most common value).
5. Set the blending mode of the layer with the High Pass filter applied to "Overlay."
6. Delete the layer below the layer with the High Pass Filter applied as it's no longer necessary.
7. Add a layer mask and fill it with black. Then paint in the areas you want to be sharper with a white brush.
8. Lower the opacity of the layer to suit your tastes. I usually end up somewhere between 50% and 90%.

Step 1

Create a stamp visible layer of your image so far using Shift+Ctrl+Alt+E on Windows or Shift+Command+Option+E on Mac. This will put all of the work you've done on the image so far in to a single layer, similar to if you were to save the image in its current state as JPEG (etc.).

Step 2

Duplicate the new stamp visible layer. This duplicate will become the sharpening layer.

Step 3

Navigate to the top menu Filter > Other > High Pass to apply the filter to the top layer.

Step 4

Here I enter a value of 3.5 pixels but this is trial and error. In my experience, 3–4 pixels is about right, sub-3 and the sharpening becomes negligible and would not be noticeable unless the image is viewed on a very large scale. Anywhere around 5 and further north and the image becomes contrasty, grainy, and minute blemishes in your image become pronounced. If you're not sure, stick to 3.5.

Step 5

Set the blending mode of the layer with the High Pass filter applied to "Overlay."

Step 6

Delete the layer below the layer with the High Pass Filter applied as it's no longer necessary.

Step 7

Add a layer mask and fill it with black. Then paint in the areas you want to be sharper with a white brush. As you can see below, I sometimes use varying brush opacity, flow, and hardness. I often want certain areas to be sharper than others even though they are both in focus to add slightly more (and I do mean slightly) emphasis on to the subject, in this case, the watch. On occasion, I only paint in the details of the subject and leave things like the watch face masked. This is time consuming but can be useful if there are plain uniform surfaces that are getting noisy when sharpened.

Step 8

Adjust the opacity of the sharpening layer to suit your tastes and image. I would say my most common value is 60–70% but it can vary from 50% through to 90%. This value is highly dependent on the quality of the image going in. If it's a bright, well-exposed image shot at low ISO with few shadows, you can get away with even 100% at times. If it's a low-key image with higher ISO, be vary careful going above 60%.

Here is a 100% crop before and after of the above image. The changes are very subtle and they're meant to be. I realize that this method of showing the effects is flawed as the example images are scaled down, but nevertheless this is the method I use in almost all of my images. Pay particular attention to the Henry London logo in the below example.

Here is another example where I used the technique to bring out the detail in a subject's eyes.