1.Most regular paper from most suppliers is cellulose (from trees) and has a high ph.(acid content from the processing)this causes it to yellow over time, and also leach the colours from a print.So if you are doing a poster on it, it has no archival qualities in the fine art sense. However it is cheaper.
2. Keeping point #1 in mind, some of their papers will have a percentage of rag content (made from cotton) and will be treated to ensure it has a neutral ph, this is better.(ask for archival or acid free)
3. With waterbase inks, the thicker the paper the better the resistance to stretching and puffing when printed - dimesional stability is the word. so you want index or cover weight, check the samples.
4. I like matte coated, it takes a better print, but with little gloss. Uncoated papers absorbe the inks more, this affects the finish/look of the inks.
5. for high end art prints (gigposters or otherwise) many printers choose 100% rag, which is not avialable from most large paper suppliers. This is 100% cotton (no trees), neutral ph (no acids), and is considered the most archival. Stonehenge, Coventry rag, Arches, and others are the brand names/manufacturers. Unfortunately, this paper is very expensive compared to regular fine papers.
6. If some of the prints are for display or street use, then run them on the cheaper paper, and run your signed and numbered on the better rag paper.
7. In vancouver, you can get rag paper at Opus. Coast paper and Unisource are the two biggie paper suppliers to the offset trade, they have sample books full of different brands, wausau being only one. coast used to carry a paper called buckeye which is 100% rag. Ask the suppliers if they have acid free, which would be your best economical choice if you want the best of both worlds.
8. If you are undecided, order some of a few different brands, mark them before printing so you can tell them apart, then run them with the run. You can then observe the different characteristics of the paper and how the ink goes down, and make a decision for future print projects.
Hey Andy...My coast ride got put off 'cause my starter died on the bike, just got a new one and a new back tire, but ran out of time. So no visit in the forseeable future. ( I was looking forward to it!)
Minneapolis/SGIA next week, the Yukon the week following, by the time I get back it will be snowing...