The BPI Spectrometer covers wavelengths from 350nm to 710nm with a resolution of better than 10nm. The transmittance spectrum results may be used for quality control purposes, such as comparing tinted lenses as well as providing information about what tints need to be added to match the color of another lens or a customer-supplied sample spectrum.The unit is a free-standing spectrometer with light sources that can also be attached to a PC via the computer's USB port. The supplied software requires Microsoft Windows. The test results can be saved to an integrated database and also can be printed out to any compatible printer. The BPI Spectrometer can also be used to see if the transmittance characteristics of a lens conform to US and European traffic signal visibility regulations. The display of the unit shows all of the information listed on the left. The PC software displays a transmission curve and allows one curve to be overlaid upon another.The BPI Spectrometer provides information on the visible transmittance (Tv) as well as the UVA transmittance of the material being tested along with the numerical color characteristics. (L*, a*, and b*). This provides a means for numerical color description. L*, a* and b* are the familiar CIELAB coordinates. L* is brightness (or lightness) ranging from 0 (black) to 100 (white). The a* value goes from about -80 (green) to +100 (red), while the b* value goes from about -80 (blue) to +100 (yellow). The PC software, in addition, displays a transmission curve and allows one curve to be overlaid upon another.