Litmus paper

Description

An unsized white paper that has been impregnated with litmus dye for use as acid-base indicator. When exposed to an aqueous solution with a pH below 4.5, the strip will turn red; with alkaline solutions above pH 8.3 the strip will turn blue. Some moisture must be present for the reaction to occur. Other natural (archil, turnsole, turmeric, and logwood) and synthetic dyes (Congo red) are used to make pH paper with varying ranges of color changes.

Synonyms and Related Terms

"litmus test paper; litmus strip; Lackmuspapier (Deut.); papier tournesol (Fr.); papier réactif (Fr.)

Authority

• The Dictionary of Paper, American Paper Institute, New York, Fourth Edition, 1980

• E.J.LaBarre, Dictionary and Encyclopedia of Paper and Paper-making, Swets & Zeitlinger, Amsterdam, 1969

• Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997

• The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998

• Art and Architecture Thesaurus Online, http://www.getty.edu/research/tools/vocabulary/aat/, J. Paul Getty Trust, Los Angeles, 2000

• George Savage, Art and Antique Restorer's Handbook, Rockliff Publishing Corp, London, 1954