Maintaining or introducing edge definition and general structure in an image is something that I often find myself challenged with. Sometimes I need to overcome flat light, back lighting or simply the lack of definition inherent in many raw images. Other times it is to reintroduce definition that was lost from the effects of another developing technique. Often it is to help showcase a feature, create a sense of dimension or create more crisp visual clarity in part of an image. There are many adjustments that can be used to these ends, both in Lightroom and in Photoshop. Clarity in Lightroom is a good starting point and the Clarity slider has been improved in the newly released Lightroom 4. Levels, Curves, Contrast and Shadow/Highlight adjustments as well as the Unsharp Mask filter in Photoshop all offer different approaches and looks. I often employ several of these methods in any given image. However, for the best combination of targeting midtone edge definition while maintaining a non-destructive workflow I find that a High Pass filter method is often my favorite.
The High Pass filter method of adding structure and definition that I like to use goes a little something like this:
- With the top layer in your layer stack selected click ctrl+alt+shift+e (cmd+opt+shift+e on a Mac). This will stamp the current state of your image to a new layer at the top of your stack called Layer.
- Rename this layer High Pass Contrast, or something like that.
- With the High Pass Contrast layer selected go to Layer>Smart Objects>Convert To Smart Object. This will allow filters you apply to this layer to be Smart Filters which can be further adjusted in the future.
- Now go to Filter>Other>High Pass. Set the radius to the number of pixels you desire. A smaller radius will increase definition along fine edges. A larger radius will create contour in large areas around edges. Since this will be a smart filter on a smart object getting the radius perfect isn’t critical. You can come back and fine tune it later. Click OK.
- The High Pass Contrast layer should now appear gray with light/dark halos around the edges in the image.
- Set the blending mode of the High Pass Contrast layer to Soft Light. This will blend the High Pass Contrast layer with the layers below, increasing edge contrast and definition at the pixel radius you set. For even more contrast you can set the blending mode to Overlay.
- You can now click on High Pass on the High Pass Contrast layer to reopen the High Pass Filter dialogue and further fine tune the radius for the look you want.
If you don’t want the High Pass contour effect to be applied to the entire image you can add a mask to the High Pass Contrast layer, fill the mask with black and then paint the effect in just where you want it with a white brush. Instead of painting on your mask you can also make a specific selection from which to create your mask for the High Pass Contrast layer.
Sometimes I will use two or more High Pass Contrast layers set to different radii so that I can paint in different degrees of definition to different areas of the image. I can also adjust the amount of the High Pass effect by changing the opacity of the High Pass Contrast layer.
This method gives a very similar affect as using the Unsharp Mask (USM) filter set to a large radius to create contrast and definition. However, a USM filter must be applied to an opaque copy layer of the image which means that any adjustment layers below the USM layer will now be rendered useless for future adjustments. Because the High Pass Contrast layer uses the soft light blending mode it is no longer an opaque layer so new adjustments made to layers below will still have affect. This makes it a more flexible and non-destructive technique.
Feel free to leave a comment or question or share your favorite non-destructive techniques for adding definition and structure to an image. If you are interested in learning more of my digital image developing workflow and techniques check out my series of video tutorials.