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As a photographer or retoucher, you learn that not all images are perfectly sharp in all the right places straight from the camera. You might make adjustments in Lightroom, Camera RAW, or in Photoshop but it often takes a little post work if your otherwise perfect shot wasn’t right on the mark.
In this retouching tutorial we’re going to look at making Photoshop work for us in a way that wasn’t entirely intended, skipping the default sharpening tools and using the often under-utilised High Pass filter to create a completely independent and editable sharpening layer.
Open your image and drag the Background Layer to the New Layer icon to duplicate it;
Select your Background Copy and choose Filter>Other>High Pass
Here’s where, and how, we choose the radius in the High Pass dialog box; small sharp details will be of a low radius while larger or more out of focus areas will be higher. In this image, choose a radius of 3 and you will see the clear water over the sand in the very lower part of the shot but the clouds will be greyed out. A low radius will sharpen the small tight details. Drag the slider to right and by 20-30 Radius you’ll clearly see the cloud detail. This higher radius will sharpen the clouds. Using masks you can use a number of layers to sharpen different parts of your image.
We’ll start with the sky and cloud detail. Here I used a Radius of 30 and clicked OK. You’ll see that there is some colour information left in the grey High Pass layer, so click Image> Adjustments> Desaturate;
To apply our grey high pass layer as a sharpening tool we can use blend modes, either Soft light, Overlay or Linear Light. Test them out, in this case Linear Light was too strong and caused banding around the sun, so I went with the middle-strength option of Overlay;
You now have a completely independent sharpening layer that can be adjusted at any point by switching between blend modes or altering the opacity slider. As with any layer you can apply a mask to filter out unwanted areas, so click the Add Layer Mask icon and with a large soft black brush paint out the lower part of the mask, leaving only the sharpened clouds we wanted;
So the nearest point at the bottom of the image started out sharp, the sky looks great, let’s take a look at the band in the middle.
Dragging the Background layer to the New Layer icon again and choosing Filter> Other> High Pass I brought the slider up to a Radius of 15 this time;
I chose Soft Light blend mode this time for a subtle effect, desaturated and painted out the sky and immediate foreground with a soft black brush on a Layer Mask, the same as we did for the clouds;
You can do this with any image, and I’ve seen a number of tutorials for High Pass Sharpening that tell you to put the slider ‘somewhere’ or give you a number to input. Now you know how to choose your own Radius you can use it for anything. Skin is a good example, want to sharpen up tight detail pores and texture? Now you know you’re going to need a low Radius for it.
A larger radius for sharpening the contours of shadows and highlight on clothing might look great, but check what it’s doing to skin, it’ll probably be awful. Use your masks wisely.
It’s usually quite enough to stop there, but I know PSDfan’s readers are always pushing for more than ‘good enough’, so the fact is High Pass isn’t 100% accurate. If you’re looking for an even more accurate method of sharpening read on and we’ll look at using the under-utilised Apply Image instead. Feel free to brag to High Pass users that you can go one better
Copy your Background Layer twice, and on the top layer use High Pass to choose your Radius, but instead of clicking OK, just hit Cancel;
Notice I’ve kept the High Pass Sharpening layers grouped in a folder for PSDfan VIP members who want to take a look at the file
Now you know your Radius (and didn’t click OK), select the bottom of the two layers and use Filter> Blur> Gaussian Blur at your chosen Radius, in this case 15 (if the top layer is visible you won’t see the effect of course);
Hit OK and select the top layer again, then select Image> Apply Image. Use the following settings for accurate results, and notice that the Layer selected in the dialog must be the layer you blurred in the last step;
Working with an 8bit image I used the 8bit settings above and clicked OK. Notice how much it resembles a High Pass layer, yet when you study the results this method is quite noticably more accurate. Delete the Gaussian Blurred layer beneath it and treat the new Apply Image layer as you would a High Pass sharpening layer. Desaturate it and set it to Linear Light, Overlay or Soft Light to your taste. Add a mask and paint in or out whatever works for you.
Told you it was more advanced, and for most applications not entirely necessary to get your head around. But if like me a few more pixels of perfection is worth your time, I’d recommend spending some time getting used to the Apply Image method.
So there’s the full High Pass/Apply Image sharpening story in one tutorial. Share it around so more people stop using one arbitrary radius for the whole image
I hope that you enjoyed this tutorial and would love to hear your feedback on the techniques and outcome.
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