What is gsm?

[GrandMasterK]

What does 200gsm mean? what about A4+?

 

[Mohain]

gsm stands for grams per square meter and is a measure of how heavy paper is.

A4+ usually means oversized (or a bit bigger than) A4. e.g. A4+ will allow an image to be printed to A4 with bleed and then trimmed down after to make a fully bled A4 image. Or a folder might be described as A4+, it needs to be big enough to take A4 inserts.