The word pixel is a combination of the two words picture and element. It is the smallest building block within a
scanned line-art or photographic image. A pixel is the small square picture element that is filled with a color, black or
white. The value of a pixel depends on the luminance of the area, and is either a single bit for a black and white
image, or multi-bit for a color or grey-tone image. Pixels come in various sizes and their size is expressed in terms of
resolution. Resolution is measured in pixels per inch (ppi) or the equivalent dots per inch (DPI.)
A computer language developed by Adobe (R) Systems, Inc. for printing text, graphics, and scanned images.
PostScript (R) is a vector format that can include scanned bitmapped images.
Also called Raster Image or Bitmapped Image. A picture composed of individual dots (picture elements, pixels) the
way a scanner perceives it. The rows in a high-resolution raster file typically contain 200 or 300 dots per horizontal
inch of the original drawing, and there are typically 200 or 300 rows per vertical inch. As each of these dots is defined
by location, and by whether it is on or off, raster images generally result in large data files.
Expressed as DPI (dots per inch) or the equivalent ppi (pixels per inch). The higher the resolution of a scanner, the
smoother the scanned images.
A measure of how many pixels per inch are scanned. Generally, more pixels per inch means more detail in the
picture and a larger file when saved. Defines the level of detail that can be captured or shown by a scanner, display,
or output device. For scanners, the resolution is defined
by the number of dots (pixels) per inch (DPI) that can be captured horizontally and vertically, e.g.
300 DPI equals 90,000 pixels per square inch. Screen Resolutions are normally 72 pixels per inch
of screen. Additional detail is thrown away by the screen display driver, anyway. For Printer Resolution scans, you
need 150 dots per inch and above for good results on the printed output. One must find the level of detail that is still
visible in printed output on the printer in question, and not dramatically increase the size of a saved file without
bettering the result.
Red, Green, Blue. These additive primary colors are the basic elements of white light. By mixing them on a computer
monitor or in a scanned image file, other colors can be created. For instance, Red and Green produces Yellow, and
equal amounts of all three produce grey.
Raster Image Processor. A RIP is a special software that converts scanned images into a color dithered (halftone)
image that can be output directly. An image must be ‘ripped’ before it can be output on a CMYK device, e.g., an inkjet
printer.
To turn the picture left (clockwise) or right (counter-clockwise) from the orientation in which it was scanned.
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