Night blue has been recommended as a substitute for basic fuchsin in the demonstration of acid fast organisms, which would be coloured blue instead of red. While this dye is effective for that purpose, small blue organisms on a red background are not as easily seen as small red organisms on a blue background, and the method has gained very little favour.

Compare this dye to its close relatives, victoria blue 4R, victoria blue B and victoria blue R. If one of these dyes is required but is unavailable, it is worth trying one of the others as a substitute.