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Photoshop - Sharpening - Highpass Method

Section Jump

fig 1

Finding the menu

Finding the high pass filter ?Ashley Beolens http://www.fatphotographer.net

I know I am not alone when I go against the grain with the way I like to sharpen my photographs in Photoshop, but when it comes to post processing, the technique I like to employ for sharpening my images doesn’t involve the usual use of the un-sharp mask or sharpening tools available in Photoshop. Instead I have found that one of the simplest and most effective ways to get an image pin sharp is with the high pass filter. I am aware that software editors may have similar filters, but this tutorial is purely for use with Photoshop. If it works the same in other photo editing packages, please let me know (or get in touch and send me an article detailing how best to sharpen in your chosen software package, we are always looking for more post processing articles).

The Process

The process I use is very simple, I start by creating a new layer {Ctrl+J}, I then select the High pass filter, from the filters drop down menu{Filter > Other > High Pass}(see fig 1), so far so easy; the next step is to set the radius levels for the filter, I usually set this to about 5.0 but this number will be dependant on your image size, and how much sharpening is required, each image can be quite different; I then select OK. What you see will be a grey picture with a faint (halo like) image of the picture below, don’t worry there is more to come. (see fig 2).

Blending

Once you have achieved a crisp looking line image, go to the layers tab (bottom right corner) and select to set this new, high pass, layers blend mode to either overlay, soft light or hard light, depending on which you feel gives the best results for your photograph. Swapping between blending modes will give you an idea of the levels of sharpness each one offers. Hard light will give the most definition while soft light will give the least; select whichever gives you the best results. It is not always easy to see the fine details of these differences in low resolution images, but we have supplied an image (see fig 3) that shows the differences in the blending options.

fig 2

fig 2 high pass box

Highpass box ?Ashley Beolens http://www.fatphotographer.net

Once this layer has been blended (don't worry blending will not alter the bottom image, this will remain as is until you mergre layers) you will then find you have sharpened only the areas that were already in focus, leaving background areas appearing much softer (I have found there is less issues with noise being sharpened with this technique); you can flick between the sharpened image and the original image by clicking the eye symbol next to the top layer. If you feel there is too much sharpening it is simply a case of reducing opacity levels of this layer.

Merge

Once you have the levels of sharpness as you want (through using the above commands) it is simply a matter of merging the layers as you normally would to complete the sharpening of your image.

As this method for sharpening your photographs in the post processing stage of your photograph, and is performed using seperate layers it allows for more selective sharpening of your image. You can bring layer masks into effect, and remove areas that are sharp enough or you don't want sharpening anymore; alterntively you can create extra layers to add emphasis to sharpening in selective sections (this is often used around the eyes in portraits). All without it looking obvious that this is what you have done (and issue I often find with other sharpening tools).

This method for sharpening uses layers and is therefore carried out in a non-destructive manner, so your original image will not be altered (unless you over save the file). What this means is that it is simple to start over if you make mistakes; you will also be making sure your original file will not be compromised.

fig 3

comparison of softlight, hardlight and overlay

Comparison of overlay styles ?Ashley Beolens http://www.fatphotographer.net

As you will see in your final image, areas you want shaprened will be crisper only where you want them to be, but elsewhere things will remain soft, and best of all you will not have issues of noise becoming sharpened or exagerated, using this method.

Here at fatphotographer we are always after well written articles on post processing techniques or how to shoot items, so please get in touch if you think you have something to contribute.