The Invert command inverts the colors in an image. You can use this command as part of the process of making an edge mask to apply sharpening and other adjustments to selected areas of an image.
When you invert an image, the brightness value of each pixel in the channels is converted to the inverse value on the 256‑step color-values scale. For example, a pixel in a positive image with a value of 255 is changed to 0, and a pixel with a value of 5 is changed to 250.
Do one of the following: