Drawing Options – Invert Image
Clicking the Invert Image check box inverts the Red-Green-Blue colors in the image. This makes black appear white, blue appear yellow, green appear magenta, etc.
Although color images are very beautiful to look at, they are impractical to print. By combining an inverted image with the Grid and Label commands, you can create a practical chart that you can use to compare the SDSS images to those from other surveys.