Dust Removal in Adobe Lightroom
Dust is less of a problem with current digital cameras than it used to be, but I was working on some older images that were not so blessed and had been inflicted with more than a few spots. After dealing with this mess, it seemed an opportune time to discuss dust spot removal in Adobe Lightroom.
If you're familiar with removing dust spots with the spot healing brush in Photoshop or the spot removal brush in Camera Raw, you'll be glad to know that the same basic tool exists in Adobe Lightroom. You'll find the Spot Removal tool in the Develop module just to the left of the eyeball (red-eye removal) icon in the Tool Strip below the histogram display. It's the one that looks like a circle with a right-pointing arrow stuck to its side. Clicking on it reveals the Spot Removal settings (tool drawer) dialog. For those who prefer keyboard shortcuts, simply press the "Q" key and you'll end up in the same place.
In order to see what you are doing, zoom in on the image until the dust spots are quite evident. You want them to appear larger than life while you work on them. It is also a good idea to use View >> Before / After to split the screen so that one side of your display will show the original image with the other side showing the results of your actions.
The Spot Removal tool operates in one of two modes. "Clone" exactly copies pixels from one part of an image to another, just as the Clone tool does in Photoshop. "Heal" attempts to match the texture, hue and lighting from the sampled area to the target similarly to the Healing Brush in Photoshop. You can think of Heal as a more intelligent, "content aware" version of Clone. For dust spot removal, set the Spot Removal tool to Heal mode. Set the Opacity to 100% and pick a Size adequate to fully cover one of the dust spots you need to get rid of.
Now just navigate around your image and click with the Spot Removal tool on each dust spot you find. When you click, drag the cursor to a similar nearby area that Lightroom can use as source data for the healing operation. Lightroom will indicate the source and target areas with circles overlaid on the image display. If you find that you didn't quite get a spot completely, you can use your mouse to freely reposition either the source or target circle as needed. You can also grab the edge of the target circle (the one around the point where you initially clicked) and drag to expand or contract it. Right-clicking on one of your edits will reveal a pop-up menu from which you can delete a Spot Removal completely if you change your mind.
Spots are most evident in the sky and other areas with little image detail such as the surface of lakes, flower petals in close-up images, and so on. For really bad images, I find it effective to systematically scan the image zoomed in, going all the way across from one side to the other, then skipping a bit and scrolling back towards the side you started on. Going back and forth, one swath at a time, you can scan an entire image fairly quickly without missing any areas. Nothing's worse than noticing a spot later when printing that I didn't initially notice.
Dust spot over Mt. Baker in the North Cascades, Before and After
All of this should seem fairly standard if you're a Photoshop user. But now comes the good part. Since dust spots on images are really dust spots on your sensor, it is generally true that a spot on one shot will be there on every shot you take until you clean your sensor. Your camera sees the same spots shot after shot. Shoot a hundred images of the sun rising over Mt. Baker in Washington's North Cascades and you'll end up with a hundred identical dust spots. It'll be there on every image. Don't ask me how I know that, I just do. Even as the camera moves and you change lenses between shots, the spots are still there since they are actually on your sensor.
While you could use the Spot Removal tool to heal the same spots on every image you took in a series, there's a better way. Lightroom makes it easy to copy all your Spot Removal edits from one image to another image, or to a whole series of images. What gets copied is the settings and where you clicked, not any of the image pixel data itself. To perform this feat, right click on the image you just got done cleaning the spots off of. Don't click on one of your Spot Removal edits themselves. You want to click in an area that hasn't been worked on. From the pop-up menu, select Settings >> Copy Settings. This will open a dialog offering a lengthy list of image attributes that can be copied. Click on the "Check None" button to clear the default copy selection check marks. Now click the single check box for Spot Removal at the top of the right-hand column and then the "Copy" button at the bottom right. The dialog will close. Now you can select one or more images shot at the same time that seem likely to have the same spots on them. It doesn't matter if some are portrait orientation and some landscape mode either. Lightroom will make the needed rotation to how it handles things automatically. Right-click on one of the selected images and choose Develop Settings >> Paste Settings from the pop-up menu to apply your edits to each of them. Since Lightroom is inherently a non-destructive image editing program, you needn't worry if this shortcut did a perfect job of each selected image. When you open each up in the Develop module, you can modify or remove any Spot Removal edits just as if you had done them directly on that image.
Dust is a fact of life (just look on top of some of your upper shelves or in the corners of your kitchen floor if you don't believe me). Not surprisingly, dust is a fact of life in photography as well. Thankfully, there are ways to get rid of dust spots in images, and Adobe Lightroom provides excellent tools for doing the job effectively and efficiently.