Abstract: In this paper, we have investigated red light development of free radical imaging system composed by a leuco crystal violet (LCV), carbon tetrabromide (CBr₄)-and 2-(p-dimethyla-minostyryl)-quinoline (2SQ), e.g. LCV/CBr₄/2SQ and LCV/CBr₄/2SQ/CHI₃, specifically, the effect of each component concentration, activators and 2SQ derivatives on red light development. It is found that 2SQ serves as sensitizing action in LCV/CBr₄/2SQ, suitable increasing the concentration of LCV did not increas the density of initial latent dye but the optical development speed increase fastly, and optical development speed or the sensitivity can be enhanced markedly by the incorporation of a small amount of CHI₂ into LCV/CBr₄/2SQ system.

Key words: free radical photography, optical development, 2-(p-dimethylaminostyryl)-quinoline