We investigate the nonlinear refraction and absorption related to holographic writing in rubidium vapor at resonance with ⁸⁷Rb D2 transition. The numerical model based on time-dependent density matrix formalism is used. The theory adequately describes nonlinear optical rotation and absorption at light intensities in the 0.1–30 mW/cm² range. The basic configurations for obtaining amplitude and phase gratings for nearly equal frequencies of writing beams are investigated experimentally, and the writing time is estimated.