Seán Duggan: Strategies for Non-Destructive Retouching (Part 1)
Apr 2013 16

Adobe Photoshop offers several key tools for retouching, such as the Clone Stamp, Healing Brush, Spot Healing Brush and the Patch tool. Other features that are invaluable for retouching include Content-Aware Fill, Content-Aware Scaling and the Content-Aware Move Tool. Although these tools can do an amazing job when you need to retouch and remove elements from images, how you use them is also an important consideration. In this article I’ll cover some essential strategies for structuring your file so that any retouching you do is flexible, adjustable and, most importantly, non-destructive to the underlying image.

Use an “Empty” Layer for Retouching

Using the Clone Stamp or Healing Brush directly on the Background layer means that you cannot edit, remove, or improve your retouching once you close the file. Although you can use the History Panel to “go back in time” and make changes to your edits during the work session, this is only available to you when the file is still open. Once you save and close the file, the history for a given work session can no longer be accessed.

Many people have been taught to simply duplicate the background layer for retouching. Unless you’re doing extensive pixel rearranging to the entire image, however, this is overkill that will needlessly add to the size of the file. In the example below using a 16-bit file from a Canon 5D Mark III, the file size jumps from 126.1MB to 253.1MB when the Background layer is duplicated for retouching purposes.

The solution that I use to add a new, empty layer above the background and use that for retouching. To do this, simply click the New Layer button at the bottom of the Layers Panel or choose Layer > New > Layer.

In order for this approach to work you need to set the Sample option to “Current and Below” for the Healing Brush and the Clone Stamp Tool. This can be found in the Options Bar for both tools (if you’re using the Spot Healing Brush, use the Sample All Layers checkbox). For simple retouching of dust spots, I typically take care of that in Lightroom, before bringing the image into Photoshop.

Current and Below allows the tool to sample data from the underlying layer, but places the new cloned or healing brush retouching on the empty layer above it. Having the retouching on a separate layer allows you to erase parts that are not working and try again.

And since there are far fewer pixels on this layer than a duplicate of the entire background, the file size increase is much less. For the 16-bit file in this example, the retouching layer used to remove the sign resulted in a file size increase of only 8MB.

Also invaluable is the ability to use the eye icon to quickly turn the layer off and on to evaluate how convincing the retouching is. To ensure that the retouching layer remains aligned with the underlying Background layer, be sure to click the lock position button near the top of the Layers Panel.

Use an Area Layer for More Extensive Retouching

For some scenarios, such as background extension or removing larger objects, the retouching you need to do cannot be done as effectively using the empty layer approach mentioned above. When using the Patch Tool for instance, the tool will not work on an empty layer; it needs direct access to pixel information in order to perform its patching magic.

Even in these situations, however, I rarely duplicate the entire Background layer; if I am only working on an area that represents say, 20% of the photo, there’s no need to copy the entire image. Instead, with the Background layer active, I make a loose selection of the area where I need to do my retouching and then turn that into a new layer by choosing Layer > New > Layer Via Copy (the handy shortcut for that is Command-J on a Mac or Control-J on Windows).

Once this layer is created I activate the Lock Position button at the top of the Layers panel to ensure that it stays aligned with the main image. Then I can use any of the retouching tools, including the Patch Tool, on this area layer, and the retouching is not permanently applied to the original image on the Background layer.

In addition to providing the flexibility to change your mind and fix mistakes you may not have seen when your first did the work, separate retouching layers also make it easy to turn your work off and on, which is useful not only for evaluating the retouching, but also for impressing clients with your Photoshop skills! I’ll take a look at some additional non-destructive retouching techniques in Part 2 of this article.

Seán Duggan is a fine art photographer and the co-author of Photoshop Masking & Compositing, Real World Digital Photography, and The Creative Digital Darkroom. He leads workshops on digital photography, Photoshop and Lightroom.