| Keyboard Shortcut | Menu Shortcut | Menu Location |
| ··· | Alt+R, O | Raster -> Erode |
The Erode command increases the size of dark regions of the image. For color images the effect can be very subtle; for black-and-white images it is usually quite noticeable.
Original color image
Eroded color image (the erode command was used twice to visually enhance the difference)
Original black-and-white image
Eroded black-and-white image (the erode command was only used once here)