Use Lineco's pH Testing Pen to easily determine if your paper and board are acidic. Draw a line on the material and check for a purple color, indicating pH neutrality. A clear or yellow color means the material may not be suitable for conservation. For long-lasting paper, aim for a pH of 6.0 or higher, with an alkaline reserve of 7.0 or greater.

Keep in mind that this is a pH indicator and may not produce accurate results for colored, coated, or unbuffered materials.