Tuesday, 9 June 2015
Analog photography vs digital Photograph
Analog photography, sometimes called chemical photography, is the term that describes the traditional or classic photograph compared to digital photography, more recent appearance. In still cameras, it is usually based on physical-chemical processes for obtaining and processing images. In analog camcorders, analog electronic sensors such as CCD or vidicon used.
Although the concept of "analogue photography" began to be used, especially since the existence of the "digital photography" to distinguish them, and that notion existed before. True, some prefer to call "chemical photography" It is based on physical-chemical processes for obtaining and processing images.
The reason is called ANALOG is because (regardless of the chemical bases of operation) that makes traditional photography is to create an analogon (ie a "like" or "almost identical" to that reality image captured) .
To obtain photographic images, in black and white in this case, film where the light-sensitive element is the silver halide suspended in very pure gelatin are used. The size and quantity of silver halide crystals determine the sensitivity of the film, commonly called speed, which is normalized and expressed in degrees ISO. When the target for a brief moment opens, light strikes the film and the impression left on her image, which at this point is called a latent image, which will be breaking from that time to be revealed. Light actually begins a physical-chemical process to produce a point of sensitivity in silver halide, thereby obtaining a latent image, which in the end, when the film is immersed in the developer, through a process of oxide reduction will occur in the processing of black metallic silver halide, thus obtaining a visible image. The developing process of black and white film consists of four basic steps: developing, unemployment and washing, fixing and washing. The image thus obtained is negative, that is, light values are inverted with respect to the original.
Once dry, this film or "negative" can make copies of the image on paper or on another film, in which case we will get a positive slide or translucent to allow us to see the photograph projected or transparency. The images obtained by investing the light values again for expansion or contact, give us results in a "positive". This process is called printing.
If we use the camera in a specially treated film, "slide" we obtain positive images directly on to develop the film.