The high pass filter is often an overlooked, if not unknown, tool in Photoshop. When used correctly, the high pass filter can add that extra touch that takes your project from looking good to looking great!
Below is a quick and easy explanation for the high pass filter in Photoshop.
Open up your image using photoshop. The image used in this tutorial can be found at sxc.hu
Duplicate the Layer. If the image has multiple layers, you may need to merge or flatten all layers before duplicating your main layer (image).
While the top layer is selected go to “Filter>Other>High Pass”
A dialog box with a preview window and a slider will appear.
The setting for the pixels radius will vary from image to image. The image size and resolution, the quality of the image, and your desired effect will all be factors that can change these settings between images. This image has been downsized to about 1800 pixels wide and the jpeg artifacting is very low making this a decent quality image. For minor sharpening and highlighting a lower setting may be desired. For a more “hdr” or “painterly” effect, a higher radius may be used. Experimentation is the key. If this is your first time using this filter, it’s okay if your image appears unusable. It will all come together in the next step.
Once the high pass filter has been applied, your image should appear grey and quite unusable. Next, with the new layer that we just ran the filter on, we will need to change the Blend mode to one of three settings: Overlay, Soft Light, or Hard Light. I have chosen to use Hard Light.
Now you should be able to see an improved difference from the original.
While the difference is slight, we can begin to see the use of this tool. But that is not all, we can take this filter much further. If we duplicate the high pass layer two times, we can see a much greater difference.
You may wonder why we duplicated the layer two times instead of running the high pass filter at a higher radius. At first, this sounds like a no brainer, but if you give it a try, you will see that you get quite a different effect.
You may notice, that the image now appears a little smudged or blurry. While this is not necessarily a bad thing, it wasn’t what we were hoping for. However, this can provide new and different results.
The high pass filter and its results are only limited by your experimenting. For example.
If you go back to step four. We had an unaltered layer. We duplicated that layer. Ran the high pass filter at a low radius setting. Set that layer to a blend mode “hard light.” Then we duplicated that layer twice. This gave us a very sharp image. We can go a step further. If we select the original layer that has not been altered, duplicate it, run the high pass filter at a higher radius setting. Set that layer to soft light, we will end up with something like this.
As you can see, the High Pass Filter offers as a powerful tool for your images. Don’t forget, in addition to the blend modes, you can also adjust the opacity setting to your layers. You can also incorporate the use of quick mask and multiple other tools to attain the exact look you are wanting.
I hope you’ve found this little tip helpful. If you find yourself confused or would like any step elaborated on, please let me know. Until next time…