A photon arrives with a wavelength. What leaves the retina is a comparison. Each preset below runs the same machinery to make a different point.
Probability that a cone of each class absorbs an arriving photon.
Color drains at the moment of absorption. After that the cone has only a count.
Absorptions per second are the absorption probability times the photon rate. Two different products can be equal.
Light A
Light B
A test light, and a mixture of three narrow primaries solved to match it on all three cone classes. A primary that would need a negative amount is added to the test light instead.
Cones, bipolar cells and horizontal cells respond with graded membrane potential. The ganglion cell's drive is the bipolar center minus the horizontal-cell surround, computed from the two traces drawn here. Spikes begin at the ganglion cell.
The gray field sets each cone's adapted level. The patch is what changes.
Maintained rate shown dashed. The signal is the excursion, in either direction.
Every dot is one patch. Broadband changes are marked separately.
The same dots, projected onto the two axes.