What is Clipping
In Lightroom the histogram will show a spike to the left if under-exposed and to the right when over-exposed. When the concentration is bunched up against the edge of the histogram, we know that significant detail has been lost in the image. This loss of detail is referred to as clipping.
Tiny Triangles
In the Develop module of Lightroom, there are tiny triangles at the top of the histogram. These tiny triangles can be of great assistance when trying to pull details from the highlights or shadows of your images. These are the clipping indicators for the highlights and shadows.
Clipping occurs when you see spikes at either end of your histogram. Those spikes indicate that you are losing information in that image. Even though you can see the spikes in the histogram, it can sometimes be difficult to look at your image and see where that information is being lost. The clipping indicators can help you locate which areas of your image are being clipped.
Seeing is Believing
One way to see where your images are being clipped is by hovering over the triangles. Hovering over the highlight clipping indicator (the one on the right) will show all the blown out highlights by masking them red.
Hovering over the shadow clipping indicator (the one on the left) will show all the blocked shadow areas by masking them blue.
While this method can be helpful, it is difficult to adjust and hover, adjust and hover. Lucky for you, you can just click on either (or both) of the clipping indicators and keep the red and blue masks active. If you’re a keyboard shortcut kind of person, just press the J key to turn both indicators on or off.
How to Recover
Now with the clipping masks active, make your adjustments using your sliders and you will see your masked areas begin to shrink, giving you immediate feedback on your progress of recovering the overblown highlights or blocked shadows!
Using these clipping indicators will help to bring life back to your photos.