33 Incredible Shadows Which Will Make You Look Twice

This is known as the Shadow blister effect. The outlines of the shadow zones can be found by tracing the rays of light emitted by the outermost regions of the extended light source. The umbra region does not receive any direct light from any part of the light source, and is the darkest. A viewer located in the umbra region cannot directly see any part of the light source. By contrast, the penumbra is illuminated by some parts of the light source, giving it an intermediate level of light intensity.