Litmus is a water-soluble mixture of different dyes extracted from lichen. Dyeing filter paper either red or blue with this ink creates one of the oldest forms of testing alkalinity and acidity. Red litmus paper turns blue under alkaline conditions. Sold in boxes of 100 strips of paper.

Litmus is a water-soluble mixture of different dyes extracted from lichen. Dyeing filter paper either red or blue with this ink creates one of the oldest forms of testing alkalinity and acidity. Blue litmus paper turns red under acidic conditions. Sold in boxes of 100 strips of paper.

The wide range test paper has a range of 1 to 14. It allows you to test the acidity or alkalinity of a solution with more accuracy than the pass/fail nature of red and blue litmus paper. The package contains 100 strips of wide range test strips and one-color indicator card ranging from 1-14 pH.