With previous code, grayscaleOffset was modifying all image components (including alpha), instead of only the color components. This commit fixes that by using a `RescaleOp` instead, which allows for distinct modifiers per component.
With previous code, grayscaleOffset was modifying all image components (including alpha), instead of only the color components. This commit fixes that by using a `RescaleOp` instead, which allows for distinct modifiers per component.