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the dpi, the more detail in an image. DPI varies, depending on the output device. A
web-page resolution is almost always 72 dpi; a printer 300-1440 dpi (varying
according to the printer).
Driver
- An integral piece of software that provides a computer the necessary
information to communicate with a peripheral device. For example, you must install a
specific driver for each device (printer or scanner) attached to your computer. Most
peripherals that are sold come with the driver stored in a disc, or the drivers are
available by visiting the company's Web site for downloading.
Exposure
- The amount of light in an image. The exposure of an image can be
changed by increasing or reducing available light.
Gamma
- The contrast affecting the mid-level grays or midtones of an image.
Adjusting the gamma of an image allows you to change brightness values of the
middle range of gray tones without dramatically altering the shadows and highlights.
Gigabyte (GB)
- A measurement of storage capacity. One gigabyte equals 1,024
megabytes.
Grayscale
- An image type that contains more than just black and white, and
includes actual shades of gray. In a grayscale image, each pixel has more bits of
information encoded in it, allowing more shades to be recorded and shown. 4 bits
are needed to reproduce up to 16 levels of gray, and 8 bits can reproduce a photo-
realistic 256 shades of gray.
Highlights
- The lightest portions of an image.
Histogram
- A graphic representation of how bright and dark pixels are distributed
in an image. A histogram skewed heavily to the left indicates a dark image, while a
histogram skewed to the right indicates a bright image.
Hue
- The characteristic of a color that distinguishes it from another color; i.e., what
makes a color red or green or blue.
Interpolated resolution
- Resolution enhanced through software; also known as
software-enhanced resolution. Interpolated resolution may capture less detail than
optical resolution, but it is useful for certain tasks, such as scanning line art or
enlarging small originals.
Maximum monitor resolution
- The number of individual dots of color, or pixels,
contained on a display. Resolution is typically expressed by measuring the number of
pixels on the horizontal axis (row) and the number of pixels on the vertical axis
(column); e.g., 640x480.
Megabyte (MB)
- A unit of computer memory capacity equal to 1,048,576 bytes.
Midtones
- The parts of an image between the lighter and darker areas, at around
50% gray.
