Rather than measuring color and value absolutely, our vision detects only spatial and time (temporal) changes in these quantities. We are standing outside on a partly cloudy day with the sun shining out from behind the clouds, illuminating the surroundings with bright and warm colored sunlight.  When the sun goes behind the clouds, at first the surroundings seem to become very dark and cool in color because our vision is contrasting this moment to the previous moment when sunlight prevailed. After a few seconds the effect of this time change in color fatigues and the view seems to become lighter and the cool cast that we see everywhere gradually gives way to our seeing more of a balance between warm and cool colors. Similarly, when the sun comes back out, at first we experience the jarring sudden transition by seeing a brilliant warm cast to the surroundings which again fatigues over time gradually to become darker and more balanced between warm and cool colors. These transitions have been sped up to heighten your awareness of them. This movie goes through two cycles of the sun going in and out from behind the clouds.