To keep a long story short: Don’t use them. I am talking about the outer lines of shapes, text boxes, tables etc. For some reason, many people seem to think that objects in Powerpoint “need” an outline (otherwise, they wouldn’t be used so frequently…). But why? They don’t have any real use and are therefore redundant. My former supervisor used to say “They don’t add any value”. This might be a strange way to put it, but in essence, he’s right. They just don’t serve any purpose, so why use them? Any shape looks just much cleaner, more elegant and more stylish without outlines.
Check the following example: