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GLOSSARY
BRIGHTNESS The lightness or darkness of the image.
CHANNEL The component of an image. Your scanned image has three channels:
red, green, and blue (RGB).
CONTRAST The gradation of shades in an image. A high contrast image has very
dark areas and bright areas without many middle shades. A low contrast
image has many tones that are close to the same brightness. Low
contrast images are often described as looking ‘flat’.
CROP To trim and delete the unwanted edges of the image.
DPI Dots (pixels) per inch.
EMULSION SIDE The side of the film coated with the photographic material.
GAMMA The contrast of only the middle tones.
HIGHLIGHTS The lighter areas of the image.
HISTOGRAM A graph showing the amount of each level of the 256 brightness levels.
IEEE 1394 Refer to the page 106.
INTERPOLATION A methord of adding new pixels to an image when resampling up.
JPEG The JPEG (Joint Photographic Experts Group) compression standard is
capable of producing a high compression ratio while maintaining image
quality. JPEG is a widely supported image file format.
MIDTONE The middle shades of an image, in between light and dark.
NEUTRAL Having no colour cast, such as black, white, or grey.
PICT (Macintosh operating system only) The PICT graphic file format uses a
lossless compression scheme and is compatible with many Macintosh
applications.
PIXEL Abbreviation for picture element. The dots that make up an electronic
image.
RESAMPLE To change the number of pixels in the image. If pixels are discarded
when shrinking an image, it is called resampling down. If new pixels are
created in an image, it is called resampling up (see page 89).
RESOLUTION The number of pixels in a given area of the image; such as pixels per
inch or pixels per centimetre. High resolution is the term for an image
with a lot of pixels in a given area. Low resolution means there are not
many pixels in a given area.
