Fig. 5. Modelling of the shift in spectral sensitivity induced by photoreceptor
screening pigment when accumulated near the rhabdom on the basal photoreceptor
R9. (A) The screening pigment, with a transmittance spectrum given by the
dashed curve (compare the red reflectance spectrum in
Fig. 4 and see text), acts on
four different visual pigments, peaking at 530, 550, 570 and 590 nm
(continuous curves). The absorption by the visual pigments (dotted curves) is
obtained by multiplying the absorption spectrum of rhodopsin by the filter
transmittance spectrum. (B) Normalizing the resulting spectra yields the
sensitivity spectra. (C) Four different red filters (dashed curves) act on a
visual pigment peaking at 570 nm (continuous curve), giving rise to absorption
spectra of lower magnitude (dotted curves). (D) Normalization yields the
sensitivity spectra.
