Orcein (Orcein, archil, orchil, lacmus, litmus, orcein, orsin, litmus, E182) — dark brown crystals. They change color to red in an acidic environment and blue in an alkaline one. Chemical formula C28H24N2O7.
The additive was excluded from the list of “Food additives for food production” to the Sanitary and Epidemiological Rules and Regulations (SanPiN 2.3.2.2364-08) in 2008.