Nekoosa papers are all acid-free and manufactured to provide maximum resistance to change and maximum life expectancy. Nekoosa paper possesses the following archival properties as specified by ASTM and TAPPI: Maximum Life Expectancy, LE-1000 (ASTM, D-3290), pH range of 9.5-10 (TAPPI T-509), Assured alkaline reserve of no less than 2.0% (ASTM D 4988-89), Residual lignin not to exceed 1% (TAPPI T-236 cm-85).
The company assured me that all their papers are acid-free and lignin-free, so the above should apply to all of their papers.
Another paper company that lists their papers as acid-free is Domtar. They make Plainfield Plus Opaque, and Windsor Offset among others.
At the Open House at Fine Papers last fall, I checked on all the paper companies represented there, and several of them have all acid-free papers, while everyone has at least some of their papers acid-free. You can check any paper for acid content with a special pen that can be purchased at any company that sells archives material.
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