Litmus 36024 - 5gr

Litmus is a blue-violet dye derived from more or less gray lichens. The dye was formerly obtained by slowly dripping water from Rocella tinctoria lichens. Since the 18th century, it has been extracted from southern lichens using alkalis such as ammonium carbonate. Litmus has the property of changing color depending on the pH; at an alkaline pH (greater than 7), it is blue, while at an acidic pH (below 7), it is red. The dye can be dissolved in water with gum arabic or a water-based binder and is quite lightfast.