The H2O2 - SO32- - Fe(CN)(6)(4-) system, one of the pH oscillators, is shown to be sensitive to visible light. Addition of a pH indicator, bromocresol purple (BCP), to this system is found to acquire new nonlinear interactions due to the screening effect of the indicator. The oscillatory region in a state diagram spanned by the flow rate and the irradiation light power shifts and becomes broader by the addition of indicator. This behavior is also confirmed by a simulation calculation. Because of extremely high extinction of light at 590 nm due to the indicator, it is expected that the system can be used for experiments on wave propagation and spatial patterns in thin films.