The
Invert filter inverts the colors in an image. You might use this
command to make a positive black-and-white image negative or to
make a positive from a scanned black-and-white negative.
Note: Because
color print film contains an orange mask in its base, the Invert command
cannot make accurate positive images from scanned color negatives.
Be sure to use the proper settings for color negatives when scanning
film on slide scanners.
When you invert an image, the
brightness value of each pixel is converted into 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.