What is the correct wavelength for luminescence assays?

When working with a luminescence assays, you in fact do not need to select a specific wavelength. Luminescence assays differ from fluorescence assays because no light is directed at the sample to generate a fluorescence signal. Instead light is produced as a by-product of an enzyme-substrate reaction. For example, a luciferase enzyme, in the presence of ATP, converts a substrate (e.g. D-Luciferin) to a luminescent product.

The light emitted from a luciferase reaction is quite broad across many wavelengths. Since most eukaryotes do not intrinsically generate light, background light from the sample is very low. Therefore, it is not necessary to filter out any light coming from a luminescence assays. In fact, most luminometers will collect light from the entire visible spectrum. This results in a very sensitive assay with low background.