The green room

For us to be able to see colours, we need white light. This is why the hand looks normal in the hole lit with white light. In the other hole, the hand looks green because the light is green.

Where can you see this?

Our eyes are good at seeing light, and are most sensitive to yellow-green light. Our eyes are less sensitive to blue and red light. But for plants it is different. The plant’s chlorophyll takes up blue and red light better, and reflects away the green light. However the most effective growing light is white, because it includes all the colours.