Difference

This transformation lets you subtract one image from another and display the difference. Using this transformation, you can see even very subtle differences between two versions of an image.

Amount

The amount control lets you control how much of the difference transformation is applied to the input image. You can apply a percentage of the transformation to the entire image, or you can specify an amount mask to restrict the effects of the transformation to only part of the input image.

Subtract Image

This image picker control lets you select the color or image to be subtracted from the input image.

Operation

This control lets you select how the difference is computed.

Difference -- causes the subtract image to be subtracted from the input image. Everywhere the subtract color or image is brighter than the input image, the result is black.

Reverse Difference-- causes the input image to be subtracted from the subtract image. Everywhere the input color or image is brighter than the subtract image, the result is black.

Offset Difference-- generates an output image that is a mid-level gray where the input and subtract images are the same. The output image is darker where the subtract image is brighter than the input image and lighter where the subtract image is lighter than the input image.

Offset Reverse Difference-- generates an output image that is a mid-level gray where the input and subtract images are the same. The output image is darker where the input image is brighter than the subtract image and lighter where the input image is lighter than the subtract image.

Absolute Difference-- generates an output image that is black where the input and subtract images are the same. The output image increases in brightness where either image differs from the other.

Strength

This slider amplifies the differences between the two images to make them more visible.