Flash infrared annealing (FIRA) of perovskite films enables manufacturing compact perovskite layers for photovoltaic devices. Here, a variable infrared pulse length to control crystal nucleation and growth in perovskite films is investigated. By varying the FIRA parameters, high-quality films are fabricated of fully inorganic and hybrid perovskites. Furthermore, film characterizations are analyzed for each FIRA protocol, unveiling the nature of the film growth. This demonstrates the versatility of FIRA and establishes it as a fast synthesis process, which provides detailed control over the perovskite morphology and crystallinity.