File Formats
Introduction
No one software program offers every option and you may want to move
graphic files from one program to another to use other options. Proper file
format is important if you plan to merge graphics into other software
programs. Review software owner/operator manuals to identify formats the
software supports for importation and exportation. Your graphics will not
display or print if you save files in incompatible file formats.
File formats
File formats are machine languages that save each binary digit or bit in a file
according to special codes that tell the program how to arrange and present
the information. Special codes for one program are not necessarily the same
special codes for other software. Two common ways files are saved to disks
are by vector and raster bit maps.
VECTOR-BASED: Vector-based drawings or object-oriented graphics are
plotted by a series of points that define paths for lines to follow. The points
are the result of mathematical formulation and most vector-based software
automatically recalculates subsequent changes. For this reason, vector-based
drawings are simpler to edit than raster-based images. Vector images are
defined by lines, shapes, color or fill pattern, and objects. Vector-based
graphics printed or viewed on low resolution printers and screens, curves and
circles appear mechanically awkward or jagged. The term for jagged edged
lines is pixilated.
RASTER-BASED: Raster-based images are images created pixel by pixel
within a matrix. Raster-based software automatically determines when and to
what number to reduce pixels in a matrix. Vector-based bit maps can be
“rasterized” or converted by a raster image processor (RIP) to raster bit
maps. The purpose of conversion is to ensure reliable transport into the
publishing software by dramatically increasing the dots per inch (dpi)
resulting in very high resolution. Rasterizing images removes the jagged
edges often associated with vector graphics reproduced at low resolution
(lower dpi). Subsequent editing in raster-based software is often difficult and
may require re-converting to vector-based software.
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