Laser flash photolysis spectra of chromophore extracts from Blepharisma japonicum cells have been measured. The variation of the triplet state spectra with pH is reported and the related pK(a) values of 2-3 for deprotonation of the excited triplet state was determined. The anionic Blepharismin triplet state does not appear to readily undergo one-electron reduction by mild reducing agents, but undergoes oxidation by benzoquinone. Pulse radiolysis has been used to independently determine the spectra of the one-electron reduced and one-electron-oxidised forms of Blepharismin.