LITMUS
Is a blue dye extracted from various species of lichens. Although these lichens grow in many
parts of the world, almost all litmus is extracted and packaged in Holland. Litmus is red at
pH 4.5 and blue around pH 8.3. While most litmus is used to make litmus papers, some is
used as a coloring for beverages.
LOGWOOD
Is a dye obtained from the heartwood of a tree that grows in Central America and the West
Indies. The extract contains hematoxylin and hematein, which turn bright red in alkaline
solution