Monday, July 09, 2007

Types of Photographs

Today, most traditional photographs are produced with a two-step chemical process. In the two-step process the film holds a negative image (colours and lights/darks are inverted), which is then transferred onto photographic paper as a positive image. Another widely used film is the positive film used for producing transparencies, usually mounted in cardboard or plastic frames called slides. Slides are widely used by professionals mostly due to their sharpness and accuracy of colour rendition. Most photographs published in magazines are taken on colour transparency film.

Originally all photographs were monochromatic, or hand-painted in color. Although methods for developing color photos were available as early as 1861, they did not become widely available until the 1940s or 50s, and even so, until the 1960s most photographs were taken in black and white. Since then, color photography has dominated popular photography, although the black and white format remains popular for amateur photographers and artists. Black and white film is considerably easier to develop than colour.

Panoramic format Images can be taken with special cameras like the Hasselblad Xpan on standard film. Since the 1990s, panoramic photos have been available on the Advanced Photo System film. APS was developed by several of the major film manufacturers to provide a "smart" film with different formats and computerized options available, though APS panoramas were created using a mask in panorama-capable cameras, far less desirable than a true panoramic camera which achieves its effect through wider film format. APS has become less popular and will be discontinued in the near future.

Digital photos are stored on computers in various file formats, of which JPEG is the most popular. Many other graphic formats are used, including TIFF and RAW.

An archival digital print is digital photographic process that results in an image display life of 100+ years, if displayed indoors under glass. Special acid free archival inks or pigments are printed directly on acid free archival art papers. Ultrachrome, Ilfochrome, and Archival Pigments are examples of commercial inks available for the production of archival digital prints. Velvet Fine Art Paper, 100% Rag, Canvas, Enahnced Matte, Watercolor Paper, Premium Ultra Glossy and other papers are examples of printable media used in arvhival digital printing.

The process requires special printers designed for the process, such as inkjet printers, IRIS printers, carbon pigment printing, or other similar processes. Recently, Epson, Canon, Hewlett-Packard, and other manufacturers have developed recreational use printers (as compared to industrial use printers) that are quite reasonable in price, enabling individual artists, students, and afficcionados to print at home.


The first permanent photograph was made in 1826 by a French inventor, Joseph Nicéphore Niépce, building on a discovery by Johann Heinrich Schultz (1724): that a silver and chalk mixture darkens under exposure to light. Niépce and Louis Daguerre refined this process. Daguerre discovered that exposing the silver first to iodine vapor, before exposure to light, and then to mercury fumes after the photograph was taken, could form a latent image; bathing the plate in a salt bath then fixes the image. These ideas led to the famous daguerreotype.

The daguerreotype had its problems, notably the extreme fragility of the resulting picture, and that it was a positive-only process and thus could not be re-printed. Inventors set about looking for improved processes that would be more practical. Several processes were introduced and used for a short time between Niépce's first image and the introduction of the collodion process in 1848. Collodion-based wet-glass plate negatives with prints made on albumen paper remained the preferred photographic method for some time, even after the introduction of the even more practical gelatin process in 1871. Adaptations of the gelatin process have remained the primary black-and-white photographic process to this day, differing primarily in the film material itself, originally glass and then a variety of flexible films.

Color photography is almost as old as black-and-white, with early experiments dating to John Herschel's experiments with Anthotype from 1842, and Lippmann plate from 1891. Color photography became much more popular with the introduction of Autochrome Lumière in 1903, which was replaced by Kodachrome, Ilfochrome and similar processes. For many years these processes were used almost exclusively for transparencies (in slide projectors and similar devices), but color prints became popular with the introduction of the Chromogenic negative, which is the most-used system in the C-41 process. The needs of the movie industry have also introduced a host of special-purpose systems, perhaps the most well known being the now-rare Technicolor.

Friday, January 19, 2007

Photographic Images

A photograph (often shortened to photo) is a single image created using a record of light falling on a light-sensitive surface, usually photographic film or a CCD. Most photographs are created using a camera, which uses a lens to focus the scene's visible wavelengths of light into a faithful reproduction of what the human eye would see. The process of creating photographs is called photography.

Motion pictures, such as film or video, are not generally considered to be sequences of photographs.