Sat Telegraph

[mojean]

Orange-red dyes that take their name from their similarity to nasturtium colours

[Norman G]

Tropaeolin

(n.) A name given to any one of a series of orange-red dyestuffs produced artificially from certain complex sulphonic acid derivatives of azo and diazo hydrocarbons of the aromatic series; -- so called because of the general resemblance to the shades of nasturtium