Cranes's Museo card stock is made from 100% cotton, using naturally pH-neutral, well water.

Many paper mills use river water, which often requires treatment with acidic alum to coagulate contaminants which is then removed by filtration.

Pure well water requires no pre-treatment. Plus, well water is high in calcium which is a buffer and maintains pH neutrality in the paper. Crane's Museo is acid-free and is manufactured without the use of optical brighteners. Each sheet is subject to Crane's rigorous quality inspection.

The base paper for Museo card stock is made to archival standards:

• 100% cotton, which has the highest percentage of alpha cellulose (the purest form of cellulose)
• buffered with calcium carbonate
• no fluorescent whiteners added
• use of naturally occurring pure Artesian well water
• acid-free