Rod and cone signal processing in mesopic heterochromatic photometry

Heterochromatic photometric measurements have been compared as assessed by two colour normal observers using heterochromatic flicker photometry (HFP) and direct comparison brightness (DCB) matching at 10 mesopic levels (3* 10-3 to 102 phot td) and five short wavelengths (413, 432, 445, 465 and 480 nm) against 506 nm.