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Friday, August 8, 2008


A photograph (often shortened to photo) is an image created by light falling on a light-sensitive surface, usually photographic film or an electronic imager such as a CCD or a CMOS chip. Most photographs are created using a camera which uses a lens to focus the scene's visible wavelengths of light into a reproduction of what the human eye would see. The process of creating photographs is called photography
There are to type of photographs:the non-digital and digital photography
Non-digital photographs are produced with a two-step chemical process. In the two-step process the light-sensitive film captures a negative image (colors and lights/darks are inverted). To produce a positive image, the negative is most commonly transferred (printed) onto photographic paper. Printing the negative onto transparent film stock is used to manufacture motion picture films.
Alternatively, the film is processed to invert the negative image, yielding positive transparencies.Such positive images are usually mounted in frames, called slides.
Originally all photographs were monochromatic, or hand-painted in color.Since then, color photography has dominated popular photography, although black and white is still used, being easier to develop than color.
The advent of the microcomputer and digital photography has led to the rise of digital prints which are created from stored graphic formats such as JPEG,TIFF and RAW.The types of printers used include inkjet printers,dye-sublimation printers,laser printers, and thermal printers.
Digital photography is a form of photography that utilizes digital technology to make digital images of subjects.The quality of a digital image is the sum of various factors, many of which are similar to film cameras.
1.Pixel count (typically listed in ,megapixels, millions of pixels) is only one of the major factors, though it is the most heavily marketed.
2.An other important factor is the lens quality which includes resolution,distorsion,dispersion.Resolution provides an indication of the amount of detail that is captured.
3.Capture medium: CMOS, CCD,Negative film,Reversal Film etc.
4.Capture format: pixel count, digital file type (RAW,TIFF, JPEG),film format (135 film,120 film, 5x4, 10x8).
5.Processing: digital and / or chemical processing of 'negative' and 'print'.

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