Martin Weberg wrote:
UV filtered readings having higher response below ~420nm. How is that?
It's hard to know, but the UV filter case has a dilemma - you don't want to illuminate bellow 420 nm, but how do you measure reflectance below 420 nm ? So the result is probably something of a compromize and fudge. For UV included/FWA the result is the apparent reflectance of illuminating it with UV below 420nm. Graeme Gill.
