It is paper. It is white. It works fine in printers and does not create a lot of paper ash within the printer. I usually pick a ream up every time I can get it for one cent or free after rebate just to keep a supply at the house. They also work great as cheap monitor risers. Currently I am using six reams (three under each of my monitors as monitor risers. They are sturdy for such a use. It is also really hard to type four hundred characters on a ream of white paper to try to get the five bonus community points on the review.