Have you ever taken a moment to consider just how a picture is actually captured? The whole process seems a bit magical if you think about it, you push a button, the shutter clicks and a moment in time is captured (in varying levels of quality, depending on your equipment). Tony Hakim is using this article as a means of introducing readers to the science of photography.
Capturing the light
Boiling it down to the very basics, a photograph is essentially a recording of the visible light reflected from all of the objects in the camera’s field of view. This reflected light causes a chemical change in the film inside the camera that can then be developed, amplified or modified into a photograph. The process whereby light causes these chemical changes in film is known as photochemistry.
The film itself
I’m sure most of us are familiar with the long strips of plastic that make up the interior of a roll of film? This is the film itself, the heart of which is called the base and is comprised of celluloid around 0.025mm thick. One side of the film is then coated with layers of chemicals that cause photochemistry to happen. Not all of the layers capture light; some contain sub-micron sized grains known as silver-halide crystals which act as photon detectors. These layers act as what we typically know as filters, as in, they filter the light in order to achieve a desired effect.
Taking the picture
The first step towards taking a picture is finding the right levels of focus and exposure. This used to be a matter of manual tinkering, but nowadays most cameras are able to automatically detect the proper settings. Once you’ve actually pushed the button though, that’s when all of the interesting chemical reactions occur.
Of course, all of this only scratches the surface of the science behind photography. Tony Hakim recommends that you continue research if this article has piqued your interest.