First, what is the “Sharpening Mask?” It is when you’re applying Sharpening, but you don’t want the sharpening to affect the entire image. For example, if you’re sharpening a bridal portrait and you don’t want her skin sharpened, or you’re sharpening a landscape shot and you don’t want the clouds sharpening. When you use the Masking slider (in the Detail panel), it removes the sharpening from those areas as you drag the slider ot the right. On Lightroom on your desktop or laptop computer, you see a preview of which areas are being masked by holding the Option key and then dragging the slider. The areas that appear in black are no longer be sharpened. It makes it really easy to...