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 RS232 port. The supplied software requires Microsoft" Windows" and PC. (Not included in purchase). The test results can be saved to an integrated database and also can be printed out to any compatible printer. 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 displays a transmission curve and allows one curve to be overlaid upon another. BPI Spectrometers utilize a spectrometer chip (micro spectrometer mounted on a linear CCD detector array) to produce a survey type spectrometer with a resolution of about 10nm. The entrance slit is a 300 micrometer optical fiber. The reflection grating has 625 lines/mm with a blaze wavelength of 560nm. The dispersion is 0.12nm/micrometer. The wavelength reproducibility is about 0.1nm. The exit slit is a 256 pixel linear photodiode array. The visible light source is a high temperature incandescent bulb. The UV source is a phosphor broadened mercury vapor tube.