Black's Photo Glossary
# A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
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RAM
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Random Access Memory. Memory that is used to hold actively used information and that can be read and erased in random sequence. RAM is volatile memory, that is, it does not save its contents when power is turned off. Image processing applications such as Photoshop require a great deal of RAM due to the large quantity of data being processed.
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RAW
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An uncompressed and unaltered image format that records exactly what the camera’s image sensor records. Although it takes up more memory than JPEG images, thus reducing the number of pictures that can be stored on a memory card, RAW format is the preferred format of professional photographers because it provides the unaltered and uncompressed image data that can be manipulated and edited using the high end features of software such as PhotoShop. The ability to save to RAW format is a feature of high-end compact cameras and Digital SLRs.
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RECHARGEABLE BATTERY
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A multiple-use battery that can be restored to its full charge and re-used repeatedly. See also BATTERY CHARGER.
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RECYCLE TIME
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1) The time it takes a digital camera to process and save a picture to memory. 2) The time it takes for a digital camera to get ready to take the next shot.
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RED EYE
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A problem created by photographing a subject with a flash. The flash reflects the blood in the retina reddening the subject’s eyes.
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RED EYE REDUCTION
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A camera feature that fires one or more bursts of light before taking a flash picture to reduce the size of the subject’s irises and to consequently reduce or eliminate red eye.
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RED EYE REMOVAL
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The removal of red eye from photographs. A function in many imaging programs and also a service offered by photo finishing labs.
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REFLECTOR
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A surface used reflect light onto the subject, usually made of shiny metal, white cloth. Or cardboard.
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RESIZING
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Altering the size of an image to change the number of pixels that it contains.
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RESOLUTION
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The number of pixels in an image, expressed as the total number of pixels (e.g. in megapixels), the number of dots per inch (DPI) or the number of vertical pixels multiplied by the number of horizontal pixels, (e.g. 640 x 480). The higher the resolution, the better the image quality.
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RGB
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Red Green Blue. An abbreviation of the three colours used by digital cameras and computer monitors to generate and display images. Red, green and blue are the primary colours of light and are separated to create a digital image, then recombined to display the image.
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ROTATION
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The reorientation of a portrait from landscape to portrait orientation and vice versa.
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RULE OF THIRDS
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Compositional guideline used by many photographers. The rule of thirds recommends dividing a photograph into an imaginary 3 x 3 grid (like a tic-tac-toe board) and placing points of interest at the points where the lines on the grid intersect. This is said to produce images that are more appealing than if objects were merely centred.
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