Flat

The Flat Appearance Type is not shaded, so it does not react to light or shadows. Therefore, the Flat appearance has a constant color regardless of lighting and shadows.

The Flat appearance is unrealistic and suited for tasks such as masking. A mask is an area that you can protect and isolate from changes you apply to the rest of the image.

Parameter

Color Sets a fixed color for the appearance. This color does not change regardless of the light falling on the appearance (the appearance is not shaded).