We conducted experiments to investigate perceptible black levels on displays in relation to viewing environments and test signals and viewers’ preferred luminance levels in different viewing environments. The results show that perceptible black level is 0.01-0.1 cd/m2 in a production environment and 0.1-0.3 cd/m2 in a home viewing environment, and that preferred peak luminance level is about 500 cd/m2 when watching current television pictures in a home viewing environment.