Quick De-Crack

The first thing you'll need to do, if you're following along in Photoshop while reading this, is download Decrack v1.0 here. Load the .atn file into your action list. If you're anything like me, you'll need some motivation to convince you to take this step. Maybe this before/after sequence, accomplished with 3 quick runs of Decrack on the levelized original, will work (click on the images for the full-sized versions):

                         (Click either to see enlarged)

Before	After

Let's Give it a Try

The levelized original is HERE. Open it in Photoshop and perform the following steps:

1. Run Decrack with a high-pass of 0.3.
2. Run Decrack with a high-pass of 0.3 again.
3. Run Decrack with a high-pass of 1.5.

The above steps should only take a few seconds each, and the end result is 3 new layers which mask out the majority of image damage. Toggle the last (most aggressive) Decrack layer on and off (or use the hue/contrast dialog to colorize the layer) and look for image detail that has been compromised. In this example, pay careful attention to the tie, the herringbone jacket, and reflections around the eyes. The eraser tool can easily remove such problem areas.

Now you're ready to retouch the photograph, hopefully without ever having to touch the clone tool!

How It Works

The Decrack action attempts to isolate high-contrast (sharp-edged) areas of the image and fill them with color from the surrounding areas of the image. The primary control is the high-pass filter value. A low value (e.g. 0.3) isolates only the highest-contrast areas, while a high value (e.g. 2.0) will include lower-contrast areas and may affect image detail. The default value of 1.5 is of medium aggression. Try playing with various values on the original image to see their affects.

When the action is invoked, it makes a copy of the currently visible image to work with. Make sure you hide any layers you don't wish to take part in the process. Since the result of the action is to fill damage from its edges toward the center, it may be necessary to run more than one iteration at a given level (as in the example above) in order to fill in larger cracks.

Extra Credit (more advanced stuff)

The Decrack action is biased towards correctiong damage which is lighter than the surrounding image. It uses the "minimum" filter as a fill tool. As a result, dark high-contrast noise or image content may actually grow during a run. Look at where the woman's white blouse and the dark edge intersect or the dark spot on the woman's cheek for examples. Internally, the "maximum" filter is also included in the action, but disabled. By making a copy of the action and disabling the "minimum" and enabling the "maximum" filter, you can create a Decrack varient biased towards removing dark damage.

You might also want to create 3 versions of Decrack with pre-set high-pass settings for no-nonsense (dialog-free) use. I'd suggest a delicate verion at 0.3, a medium version at 1.5, and a heavy version at 3.0 or 4.0. These settings will vary depending on the resulution of photos you work with...

This version of Decrack doesn't respect selections. Perhaps I'll get around to it at some point (it should be easy using an alpha channel to store the selection ahead of time), but until then you can mask the layers quite easily instead.

If you would like to experiment with finer control of the Decrack effect, try enabling the 'dialog' for the Brightness/Contrast entry in the action, as well as the dialog for the 'Minimum' filter.

Enjoy! Feel free to distribute freely (for free). (Ed. note: please give credit)

If you have a tutorial relevant to photo restoration, retouching, or manipulation, please email me with details and we'll either publish it here or link to it.

Discuss this tutorial here