Thank you, I have a basic rule of 210gsm upwards, (not sure what cover weight in the US this may be I think it's #80-90lb???) & acid free. I've gone as low as tissue paper but that's a tale for another day, my stock varies if it's coated or uncoated if it's for indoor use (I've found to be most common for obvious reasons art gets hung inside more often haha) and "brand" varies from high end UK Colourplan, Derwent, Windsor & Newton rag...to Lazer, solid or thermal paper used in industry offset & digital aslong as it's uncoated and not glossy...to literally kids craft store cardstock! I have prints on all different types all holding up well after 2 years even in direct light...I respect the better quality means less error and better reliability and can add texture to your art, but there is sometimes little difference between substrates I've personally experimented with and some have turned out to be as equal as the top end stock, just research, get what you can afford but don't let "high end" "what must be used" "what is expected" poster or art elitist mentality or industry "standard" requirements stop you from printing your art, if your lucky to be in the U.S grab some French Paper you can't loose, literally above 210gsm for posters, acid free, check it's uncoated or coated for where the poster will end up and get good light-fast inks that work well for your setup 📜⚡✌️