- Bleed-resistant – Colored paper should not transfer dyes under wet or humid conditions. Check this one yourself by placing the paper in contact with a piece of white paper. Use a paper clip to hold the two pieces of paper together and place them in a bowl of water for one day. The white paper should not show any dye when the paper clip is removed from the water.
- Acid-free – Uncoated, white paper can be checked with pH pens. For other papers, you will need to rely on the manufacturer’s labeling. pH pens are not reliable when used with coated or colored papers.
- Lignin-free – Skip the newsprint and construction paper. These low-cost papers generally contain lignin that will damage photos over time. They are also likely to become brittle.
- Buffered – Buffering prevents paper from becoming acidic over time. You will need to rely on the manufacturer’s labeling.
- Photographic Activity Test – Ensures that paper contains no other harmful components. This test is complicated and cannot be run at home.
To be completely safe, paper should comply with all of these ISO 18902 requirements. However, from a practical standpoint, high-quality paper that is acid-free and bleed resistant should be all right.