Computer Graphics Metafile (CGM) is a formally agreed standard. it is a 2D
vector graphic and therefore particularly suited for drawings. CGM files are
smaller than images.
CGM files can either be created by using applications
such as corel draw or via converters. CGM files have their own MIME type and
currently need an external viewer. in the future, plug-ins for Web browsers may
become available. for more information choose
this
.
Portable Document Format (PDF) is a proposed standard from adobe. it is the EPS equivalent for graphics. PDF may include text, graphics and images, the later might be in a compressed format.
this talked focused on the problem of how to provide true colors on
different screens or even different types of output devices. colors need to be
very accurate for example in advertisements, especial if it comes to fashion or
cosmetics. but also in scientific publications, it might be important to provide
true colors. the color on the screen does not only vary from one brand to
another, but might also change if the light or the background varies.
adobe
tries to solve the problem by providing a device dependent transformation of the
colors on the input device AND on the output device. but the data that will be
transferred over the net shall be in a standardized format. this would allow to
transform the data to any output device as long as the transformation process is
known for that particular output device.
Portable Network Graphics (PNG) shall become a new standard (a formal RFC exists already), the proposed MIME type is image/png. it is fast and optimized for data transfer over the network, because it is simple, robust, flexible and extendable. in contrast to GIF, PNG is legally unencumbered. PNG provides loss-less data compression. it can index color, grayscale or truecolor and supports gamma correction. data may be encoded from 1 to 16 bits per color. since PNG provides 7 pass interlacing, images will appear much faster and will transform from a rough to a more detailed picture smoothly. data files contain metadata as text.
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