It depends on what was being printed. For mass market books and magazines, pulp paper was dominant in this period, in Europe and North America. For deluxe editions and intaglio prints, you'd find rag paper, which was more expensive and sturdier (also more archival--pulp paper tends to be acidic and turn crumbly with age). There are all kinds of exceptions and specialized uses--again, a better sense of the kind of printed matter in question would help.