Data protection function to avoid abnormal termination such as bugs. The Overlay mode behaves like Screen mode in bright areas, and like Multiply mode in darker areas. Add (Glow) The Add (Glow) mode creates a stronger effect than Add. In digital terms, adding color increases the brightness. I just prefer the way SAI produces lines. The Add mode adds the color information of the base layers and the blending layer. This is not at all necessary and all linework can be done in Photoshop using a hard basic brush at size 1 or 2. This means I have to CLICK on each blending mode, instead of just passing the cursor over it, to see what I'm doing. At a few points I switch to using Paint Tool SAI to do some of the linework. Simple but powerful user interface, easy to learn. The problem is this: when I move the cursor on the dropdown menu of the blending modes, my layer preview doesn't change at all so I basically can't see a preview of the changes on my canvas. Highly accurate composition with 16bit ARGB channels.