Analogue is a wave which is recorded or used in its original form. For example, in an analogue music and speech differ constantly in frequency and amplitude, just like how analogue signals can vary in frequency , amplitude or both. An example is FM and AM radio - Frequency Modulated radio and Amplitude Modulated radio. The diagram shows a typical oscilloscope trace of an analogue signal.
Digital
Digital signals are a sequence
of pulses consisting of just two states which are ON (1) or OFF (0). There are no
numbers or values in between. DAB radio is Digital Audio Broadcast radio - it
is transmitted as digital signals
How do analogue and digital relate to film?
Film, as we know, can be a 'chemical' or digital process. When it is a chemical process a light sensetive silver halide emulsion coated on a film base is exposed to light in a camera. This creates a latended image which is made visable by emersing the film into a chemical solution which we refer to as a 'developer' a print can then be made by projecting the image from the film onto sensitized photographic paper and processing the paper through a number of chemical baths. Digital imaging does not require chemicals, digital images are captured using arrays of photo sensers and these images are then processed by specialised software, prints can be made through ink jet printers. In everyday speak people commonly refer to chemical photography as analogue to contrast it with the digital process, here, analogue is refering a signal whos output is propotional to the input. A good example for analogue in tradicional photography is a light meter where light falls on a photo cell which generates an electrical current moving a needle over a scale the more bright the light is the more the needle moves. Ironically, the sensor in a digital camera is also analogue: each one of the millions of pixels which constitute the sensor is a light sensetive photo cell generating a tiny electrical current which is responding to light/ the brighter the light the stronger the current.
How do analogue and digital relate to film?
Film, as we know, can be a 'chemical' or digital process. When it is a chemical process a light sensetive silver halide emulsion coated on a film base is exposed to light in a camera. This creates a latended image which is made visable by emersing the film into a chemical solution which we refer to as a 'developer' a print can then be made by projecting the image from the film onto sensitized photographic paper and processing the paper through a number of chemical baths. Digital imaging does not require chemicals, digital images are captured using arrays of photo sensers and these images are then processed by specialised software, prints can be made through ink jet printers. In everyday speak people commonly refer to chemical photography as analogue to contrast it with the digital process, here, analogue is refering a signal whos output is propotional to the input. A good example for analogue in tradicional photography is a light meter where light falls on a photo cell which generates an electrical current moving a needle over a scale the more bright the light is the more the needle moves. Ironically, the sensor in a digital camera is also analogue: each one of the millions of pixels which constitute the sensor is a light sensetive photo cell generating a tiny electrical current which is responding to light/ the brighter the light the stronger the current.
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