Back in January 2014 I wrote a blog piece about Lightroom’s “Visualize Spots” feature, which had just been introduced with the then-new Lightroom 5. Well, here we are five years later and at Lightroom Classic CC version 8.2. I recently finished teaching a workshop and was somewhat shocked that over half the attendees — regular Lightroom users — did not know about Visualize Spots. So to repeat myself…. Visualize Spots does exactly as its name suggests; it shows you all the dust spots on your image, including many that you might otherwise miss.
In the Develop module, select the Spot Tool. It’s the second tool from the left in the Develop tool bar (the keyboard shortcut for the Spot Tool is Q).
Look at the bottom left, just below your image, and you will find the Visualize Spots checkbox. Click on this, your image changes to black and white, and all those dust bunnies show up. Move the Visualize spots slider to increase or decrease the sensitivity, and start spotting.
You can change the size of the Spot Tool by using the scroll wheel on your mouse. You can change the feathering of the tool by holding down the Shift key while using the scroll wheel.
And now a neat little trick: set your image view at 100%, or 1:1, and navigate to the upper left corner of your image. Use Page Down (Windows: PgDn on a full-size keyboard; Mac (and most Windows laptops): Function + down arrow) to move the area shown on screen by exactly one screen view. When you get to the bottom of the image, do Page Down again, and the screen view moves over and up to the top. Keep doing Page Down until you’re covered the entire image. This little trick means you’ll never miss any section of the image.