Time-scheduled exposure method for full-color high diffraction efficiency and uniformity of a photopolymer

•Time-scheduled exposure method for full-color reflection recording is proposed.•The reactivity of the photopolymer to exposures is different at the three wavelengths.•The pre-exposure times of each laser are adjusted to make the diffraction efficiencies more uniform.•The full-color grating with high diffraction efficiency is verified experimentally.