:: Glossary . Not familiar with common and not-so-common photography terms? The GMg:photo glossary will help you to understand and become comfortable with those most frequently used. We will add regularly to this section to keep it current and valuable. If you don’t see what you are looking for, please Contact Us.


Aspect Ratio: The ratio of width to height in photographic prints. 35 mm images from film or digital cameras have a ratio of 2:3 which yields prints measuring 3.5 x 5 inches, 4 x 6 inches, 6 x 9 inches, etc. A ratio of 4:5 yields prints measuring 4 x 5 inches, 8 x 10 inches, 16 x 20 inches, etc. Note that many stock picture frames do not conform to the 2:3 ratio and therefore 35mm images will need to be cropped. (E.G. 5 x 7 and 8 x 10)

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Camera Angles: The angle at which a camera is located in relationship to the subject. The camera can be above, below, straight on, left, right, etc. The camera location can create a variety of visual effects and perspectives.

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Candid Pictures: Images created without the benefit (or detriment) of posing. Often taken without the subject’s knowledge, this style of image may appear more natural and relaxed than posed pictures.

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Color Cast: With film, unnatural coloring of an image due to exposure, processing or printing conditions. Also occurs in digital images captures and scanned images.

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Composition: The pleasing arrangement of the elements within a scene. Includes main subject, foreground, background, and supporting subjects. May have been arrived at using the Rule of Thirds, where key elements are placed on imaginary lines that divide the field of view into thirds both horizontally and vertically.

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Contact Print: A traditional darkroom technique where a print is made by exposing photographic paper while it is held tightly against the negative. Images in the print will be the same size as those in the negative. There is no enlargement involved.

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Contrast: Simply put, the difference in brightness between the light and dark areas of a image.

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Depth of Field: The zone of acceptable sharpness in front of and behind the subject on which the lens is focused. DOF is dependent on three factors: aperture, focal length, and focused distance; the wider the aperture, the longer the focal length, and the closer the focused distance, the less the DOF, and vice versa.

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Existing Light: (Or available light) Existing light covers all natural lighting from moonlight to sunshine. For photographic purposes, existing light is the light that is already on the scene and includes room lamps, fluorescent lamps, spotlights, neon signs, candles, daylight through windows, outdoor scenes at twilight or in moonlight, and scenes artificially illuminated after dark.

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Flash Memory Card: 
An electronic storage medium used by digital cameras. Memory cards store the image as does film in conventional photography.

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PDF File Format: 
Portable Document Format (PDF) is a file format created by Adobe Systems in 1993 for document exchange. Adobe PDF is used for representing two-dimensional documents in a manner independent of the application software, hardware, and operating system. Each Adobe PDF file encapsulates a complete description of a fixed-layout 2D document that includes the text, fonts, images, and 2D vector graphics which compose the documents.

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PNG File Format: The Portable Network Graphics format is expected to become a mainstream format for Web images and could replace GIF entirely. It is platform independent and should be used for single images only (not animation). Compared with GIF, PNG offers greater color support and better compression, gamma correction for brightness control across platforms, better support for transparency, and a better method for displaying progressive images.

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Raster Graphics Format: Also know as bit-mapped graphics format. This format is a representation consisting of rows and columns of pixels in computer memory. The value of each dot, whether it is filled or not, is stored in one or more bits of data. The density of the dots, known as the resolution, determines how sharply the image is represented. This is often expressed in pixels per inch [ppi]. To display a bit-mapped image on a monitor or to print on a printer, the computer translates the bit map into pixels for monitor screens, or ink dots for printer. Bitmap images have a fixed resolution and cannot be resized without losing image quality. Common bitmap-based formats are JPEG, GIF, TIFF, PNG, PICT, and BMP.

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Resolution: Resolution is a measurement of the output quality of an image, usually in terms of samples, pixels, dots, or lines per inch. The terminology varies according to the intended output device. PPI (pixels per inch) refers to screen resolution, DPI (dots per inch) refers to print resolution, SPI (samples per inch) refers to scanning resolution, and LPI (lines per inch) refers to halftone resolution. Often images are referred to as high resolution (hi-res) or low resolution (low-res). High resolution would be an image intended for print, generally having 300 samples per inch or more. Low resolution refers to images only intended for screen display, generally having 100 pixels per inch or less. Scanner and digital camera manufacturers often refer to two different types of resolution when listing product specs: optical resolution and interpolated, or digital, resolution. The optical resolution is the true measurement of resolution that the output device can capture. Interpolated, or digital, resolution is acquired artificially.

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RGB Color Space: One of the color spaces used in graphics software. This color space is based on the primary additive colors of [R]ed, [G]reen, and [B]lue. This is the most common color mode used in graphics software.

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Royalty Free Image License: 

A Royalty Free image license allows the licensee to use the image in any way he sees fit, for as long as he desires. The types of use allowed are limited only by terms of the licensing agreement. Royalty Free Licenses are generally less expensive than Rights Managed Licenses.

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Saturation: An attribute of perceived color, or the percentage of hue in a color. Saturated colors are called vivid, strong, or deep. De-saturated colors are called dull, weak, or washed out.

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TIFF File Format: Tagged Image File Format (abbreviated TIFF) is a file format for storing images, popular among Apple Macintosh owners, graphic artists, the publishing industry, and both amateur and professional photographers in general. As of 2009, it is under the control of Adobe Systems. The TIFF format is widely supported by image-manipulation applications, by publishing and page layout applications, by scanning, faxing, word processing, optical character recognition and other applications.

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Vector Graphics Format: Vector graphics are made up of many individual objects. Each of these objects can be defined by mathematical statements and has individual properties assigned to it such as color, fill, and outline. Vector graphics are resolution independent because they can be output to the highest quality at any scale. Common vector formats include AI (Adobe Illustrator), CDR (CorelDRAW).

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