Measures the central wavelength, peak wavelength, and the spectral width (RMS and FWHM) of a semiconductor light emitting diode (LED) using a dispersive spectrophotometric method (that is, using a revolving diffraction grating) or other suitable method. This is the second public review for this standard. It first appeared in the September 26, 1997 issue of Standards Action and is being resubmitted now due to substantive changes to the text.