About a year ago, engineering consultant Mike Wood was trying to measure the output of a tri-chromatic LED luminaire. Its pure blue output looked bright to his eyes, but his top-of-the-line photometer showed very little output. To make the matter more confusing, his least expensive light meter gave a reading that was closer to what he was seeing. What was going on?
The problem is that the standard CIE photopic luminous efficiency function, originally established in 1924 and slightly r