Effects of chromatic adaptation on phase-dependent sensitivity to heterochromatic flicker.

Temporal modulation sensitivity was measured as a function of the relative phase of two equiluminous chromatic sources (564 and 625 nm) for temporal frequencies from 6 to 20 Hz. The difference between 180 degrees and the phase of least sensitivity was computed as the measured phase shift. A 2 degree test field was superimposed upon 8 degrees chromatic adapting fields with luminances from 100 to 3000 Td and chromaticities of 500, 600, and 650 nm. For each adapting field, the 564-nm source was set to 175 Td, and the 625-nm source was matched to it with heterochromatic flicker photometry (giving an effective mean luminance of 350 Td). The 650-nm adapting fields produced large changes in photometric setting but only small changes in the measured phase shift. The 600- and 500-nm adapting fields produced smaller changes in photometric setting but larger changes in the measured phase shift. In general, increased adapting luminance resulted in an increase in the measured phase shift for 600-nm adaptation and a decrease in the measured phase shift for 500-nm adaptation.