Tyrian purple rough indication of the likely range in which it appeared: _________ <br> _________ The lower one is the sRGB colour #990024, intended for viewing on an output device with a gamma of 2.2. It is a representation of RHS colour code 66A, which has been equated to "Tyrian red", a term which is often used as a synonym for Tyrian purple. The colour name "Tyrian plum" is popularly given to a British postage stamp that was prepared, but never released to the public, shortly before the death of King Edward VII in 1910. Tyrian purple Tyrian purple (, "porphúra"; ),
Metacresol purple Metacresol purple Metacresol purple or m"-cresol purple, also called m"-cresolsulfonphthalein is a triarylmethane dye and a pH indicator that is used in medicine to detect end-tidal carbon dioxide to ensure successful tracheal intubation in an emergency as the indicator inside a colorimetric carbon dioxide detector. It can be used to measure the pH in subzero temperatures of saline or hypersaline media. In colometric capnography the indicator is incorporated in a matrix that provides a pH just above the indicator's colour change, it undergoes the colour change from purple to yellow with CO; (a yellow colour often described as gold) when