Lineco PH Testing Pen

Acidic or alkaline? Now you can distinguish between what paper or board is suitable for conservation with the stroke of a Lineco PH Testing Pen. The solution will turn a shade of purple on paper with a pH of 6.5 or higher. Any other color indicates a pH lower than 6.5, which is thereby acidic, and unsuitable for artwork that is meant to last. Paper can be respectably long-lived if its pH is as low as 6.0, especially if it is well made and carefully used and stored.

Archival art fact: in order to last for centuries in today's poor air quality, paper must have an alkaline reserve. This usually means a pH of 7.0 or greater.