Most of our history has passed with not much artificial lighting. We have spent our days in the sunlight and nights by the fire, and these are the light sources that we are still most used to. We still state the natural light to be perfect, trying to copy its qualities when developing lighting technologies. And when describing our artificial light sources, all the parameters are based on the qualities of natural light.
The Sun is a very intense and small light source very far away. All the rays from the Sun reach the Earth’s surface at the same angle, causing directional shadows. Sometimes the Sun’s rays are filtered in clouds and atmosphere, making the whole sky a large, glowing light source that gives out diffuse light. In this case the light rays hit Earth under many different angles. Under direct sunlight, shadows are very clear and dark, whereas on a cloudy day with diffuse lighting there might not be one single shadow noticeable. Usually, the daylight is a combination of these two – direct and diffuse. As clouds move and the weather constantly changes, sunlight never remains in a static state for long.
The pink backlight comes directly from the setting sun that is visible in the background. The blue hue in the shadows is diffuse light reflected from the clear blue sky.
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