visible light, uv and x-rays

VISIBLE LIGHT

we only see things because they are illuminated - they either give out or reflect light. for you to see an object, light needs to enter your eyes

when light enters your eye, it gets refracted through the lens and focused onto the retina at the back of your eye. the retina then send messages to the brain (via the optic nerve), and the brain interprets them

photography works in a similar way to the eye. cameras use a lens to focus visible light onto a light sensitive film or electronic sensor that records the image

the lens' aperture controls how much light enters the camera

the shutter speed determines how long the film or sensor is exposed to the light

by varying the aperture and shutter speed, a photographer can capture as much or as little as they want in their photograph

ULTRAVIOLET

fluorescence is a property of certain chemicals, where ultraviolet radiation (uv) is absorbed and then visible light is emitted. that's why fluorescent lights look so bright - they do actually emit light

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