Using carbon free energy sources is one of the keys to mitigate climate change. Hydrogenpromises to be one of these carbon free energies, but its storage is difficult and expensive. Ammonia,however, is interesting as it can store hydrogen safely and can be used in combustion engines insteadof hydrocarbon fuels. In this experimental work, the spray characteristics of ammonia under differentair densities and temperatures were investigated in constant volume and were compared to a biofuel,ethanol, and a common fuel, gasoline. The Schlieren technique was used to capture images ofliquid and liquid + vapor spray. The penetration length, the angle near the injector and the angleat half-penetration length were measured. The results show that the spray geometry of ammoniadiffers from that of the other fuels and that its sensitivity to air density and temperature is greater.The flash boiling condition at ambient temperature was explored for ammonia and indicated awider spray at half-penetration length at phase change. Moreover, a semi-empirical correlation forpenetration length as a function of physical parameters was found with a high accuracy for the globalspray. These experimental data provide the first information about ammonia injection with a currentspark-ignition GDI injector.