A short one, but there's a lot here. Trying a more general design topic that isn't blender specific – should I make more of these? It's a guide for blend modes – things like "multiply", "screen" and "overlay" – explained with practical examples in Photoshop, Illustrator, Indesign, Premiere, After Effects and Blender. Check out Mockup3d.com – online 3D mockups for designers – if you haven't already.