Invert - Microtek ArtixScan 4500t Reference Manual

Invert

This command inverts images of all scan jobs. Take note that all scan jobs are
inverted at the same time; you cannot invert an individual scan job alone.
When an image is inverted, the brightness value of each pixel is converted to its
inverse value. In the case of 24-bit images, 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.
Original Inverted image
To use this feature:
Choose the Invert command in the Preferences menu. A check appears next to
the command when it is enabled.
Reference: The Preview Window 35