Turmeric paper

Description

An acid indicating paper. Turmeric paper is an absorbent filter paper dye with the extract from turmeric roots. It contains curcumin which is an acid-base indicator. Curcumin is yellow with acids (below pH 7.4) and a reddish brown with alkalis (above pH 8.6). Curcumin also turns brown in the presence of boron compounds such as boric acid. Turmeric is commonly used as a yellow dye in paper made in the Punjab.