Martin Weberg wrote:
The original observation was: UV filtered reading was high below 420nm while no filter and FWA compensation was low. Since UV filtered readings contain no UV (10-400nm) I thought it was interesting that the Spectrolino fitted with UV filter produced higher reflectance then without filter below 420nm.
This response is consistent with media that has no FWA, since FWA absorbs short wavelength energy so as to re-emit it at longer wavelengths. It's not clear to me though how the UV filter would simulate the absence of FWA though. I would have thought that the apparent reflectance at short wavelengths would remain the same. Graeme Gill.
