We can show how a bright light beco

We can show how a bright light becomes darker by lighting a candle and holding pieces of tracing paper in front of it. The more sheets of paper we can use the more the light turns from yellow to red. We can see a similar process in nature. At sunrise and sunset the colours radiating from the sun are stronger. This is because the light is traversing a thicker layer of atmosphere. If we look up to the sky at night we see it as black. During the daytime we see it through light and it becomes blue. This accords with Goethe's statement that blue is illuminated darkness, yellow is darkened light. Indigo and violet on the one side are heightened modifications and orange and red on the other. Where blue and yellow meet, green is produced. We see the same phenomena looking through water. If we look at the sea from above, we see blue (dark through light). Divers looking upward from the sea-bed see reds and browns, (light through dark).