A multi-channel scanning system adapted to implement a low channel cross-talk, extra-wide dynamic range scanning method by scanning the same location more than once, wherein at least one time, the power of the excitation light and detector gain are set to High for at least one of the channels and Low for at least one of the other channels and different settings are used in subsequent scans. The scans of the same channel taken with different High and Low settings are merged together to produce one wider dynamic range image.