As a photographer or digital artist it can be very disappointing to find out your photos are not fully sharp. Or you want to add a little bit of extra sharpness to the eyes or hair. In this tutorial I will explain my most-used technique for sharpening photos without creating extra noise.
The first step is duplicate the photo to create a layer that will contain the details of the photo. Right click on the layer and then click "Duplicate Layer" or use the control CTRL + J to duplicate the layer.
Make sure you have selected the new duplicate. Then go to the top-menu and click on "Filters". Go all the way to the bottom and click on "Other" >> "High Pass" (also see the image below).
After clicking on the effect, a menu will open where you can change the properties of this filter. As you can see, the image is already converted into a grey image with glowing edges. The filter has automatically selected the edges and details of the photo and enhanced the "brightness" of them. You can increase this by increasing the amount of "Radius". The higher the radius, the more parts of the photo will be included. In this case, we only want the fine details, so the radius needs to be very small. You may have to play around with the radius, because the amount really depends on the photo. Still, a lower radius will produce more fine and detailed results. Never exceed the amount of radius where the colours of the photo begin to show. You need this layer to be grey (black/white) to be able to blend it in the next step.
Now, we are going to blend in the details layer with the original photo. Make sure the new layer with the High Pass effect is still selected. Go to "Blend mode" and change it to "Hard Light". This blends in the layer, but keep the details. These details are now applied but in a separate layer.
The "High Pass" effect creates much less noise than the normal Sharpening tools within Photoshop, but sometimes there is still some noise visible. Especially in the darker areas. But, because the details are stored in a separate layer, you can control the amount of noise and also the strength of the "High Pass" effect by simply adding a Layer Mask and paint on it. (Learn more about Layer Masks in this Tutorial).
Make sure the new layer is still selected and click on "Add Layer Mask". Click on this new layer mask to select it and paint on it with (preferably) a soft brush. When you paint with black, it will erase that part of the "High Pass Layer". When you paint with white, it will de-erase that part of the layer (Learn more about Layer Masks in this Tutorial) .
