With the proliferation of quality systems in manufacturing such as ISO9000 (a series of standards from the International Organization for Standardization), the accurate measurement of the light and color
generated by particular products has become increasingly important. Since light-emitting products are designed to be seen
by people or to illuminate other objects that need to be seen, the measurement process must take into consideration the human eye’s response to light. The field of photometry deals with the measurement of light weighted according to human visual response.