Lightroom is a great photo editor, but sometimes you need to control how the photos are displayed. For example, you might want to limit the photos to a certain range of colors or brightness levels. You can do this by using the Range Masking tool. The Range Masking tool is located in the Tools palette, and it looks like this: The Range Masking tool can be used to create masks that restrict the display of specific colors or brightness levels. The mask can be created by clicking on one of the color or brightness levels that you want to restrict, and then dragging the slider to change how high or low that level will be set at. The mask will also have a blue checkmark next to it if it has been successfully applied. If you want to remove all of the masks from a photo, just click on the None button next to any of them in the Tools palette.