Before revision: The colours of the object also become less saturated and shift toward the background colour , which is usually bluish , but may be some other colour under certain conditions (for instance, reddish around sunrise or sunset ).
After revision: The colours of the object also become less saturated and shift toward the colour of the atmosphere , which is bluish when sunlit, but will shift to other colours under certain conditions (for instance, reddish around sunrise and sunset or saturated during fog ).