Colour Time 

website, 2020
A change of colour slight enough to be perceptible, yet slow enough so that it is hard to see the change as it occurs.

The change is perceptible primarily when the eye becomes saturated with colour; the eye detects the change but the retina is overstimulated, so the colour one sees is a combination of a complementary after-image and the actual colour.

https://www.colour-time.com/