Change is permanent: thoughts on the fading of cochineal-based watercolor pigments

摘要: Color change in artworks has been commented on for centuries. Fading of watercolor pigments is a notable alteration. Pigments based carminic acid are among those particularly prone to color loss, but the mechanism and factors not well understood. We painted out three prepared from aqueous extract (CA) Dactylopius coccus: uncomplexed, aluminium- tin-complexed lakes. These were applied 2% gum Arabic solution papers that acidic, neutral or alkaline pH exposed accelerated light aging weatherometer. The comparative rate fading was dependent complexation substrate. On paper, Al complex least stable, paper colorants responded similarly, acidic tin stable. This discussed published information reactions loss CA.