Although LEDs produce a narrow spectral peak of light, there are often regions of shorter and longer wavelength illumination which may lead to increased background in the image or interfere with the excitation of another fluorophore if no excitation filter is used. We therefore always recommend that excitation filters are used with pE-Series LED Illumination Systems for fluorescence microscopy.
When selecting a microscope LED Light Source which is based on a single, or few wavelength peaks, it is essential that care is taken to match these with the excitation filter in the microscope. Alternatively, a new filter can be fitted which is matched to the microscope Illumination System and the fluorophore.
Broad spectrum illumination systems are less sensitive to this optimisation requirement but it is still beneficial to check the filters. For example, with systems such as the pE-4000, the range of available wavelengths means that LED wavelengths can be selected to match the existing filters in the microscope.