Understanding Artwork - For Better Results
When we create your brand identity on to a promotional item we want to
ensure the best possible quality, so we prefer to use Vector files such
as .EPS with the text converted to Curves (or Outline). Not sure what
we mean, below is information on images formats and types. For information
on Pantone® Colours click
here. There are two kinds of computer graphics - raster (composed
of pixels) and vector (composed of paths). Raster images are more commonly
called bitmap images.
A bitmap image uses a grid of individual pixels where each pixel can
be a different color or shade. Bitmaps are composed of pixels.
Vector graphics use mathematical relationships between points and the
paths connecting them to describe an image. Vector graphics are composed
of paths.
With Adobe® Systems' introduction of the PostScript® page-description
language computers could display fonts and images using point-to-point
math rather than by pixels alone. The advantage to using a page-description
language such as PostScript becomes clear when you scale an image up.
The larger you display a bitmap, the more jagged it appears, while a vector
image remains smooth at any size. That is why PostScript and TrueType®
fonts always appear smooth - they are vector-based.
The jagged appearance of bitmap images can be partially overcome with
the use of "anti-aliasing". Anti-aliasing is the application
of subtle transitions in the pixels along the edges of images to minimize
the jagged effect (below left). A scalable vector image will always appear
smooth.
Bitmap images require higher resolutions and anti-aliasing for a smooth
appearance. Vector-based graphics on the other hand are mathematically
described and appear smooth at any size or resolution.
Bitmaps are best used for photographs and images with subtle shading.
Graphics best suited for the vector format are page layout, type, line
art or illustrations.
Wherever possible use the vector format for all your type, line art and
illustrations and only use bitmaps for photos or images with complex or
non-uniform shading. If the graphics application recognizes native vector
files such as those created by Deneba Canvas™ (a filename with an
extension of .CNV- for versions 6 and 7), Adobe Illustrator® (a filename
with an extension of .AI), CorelDRAW® (a filename with an extension
of .CDR), or Macromedia® FreeHand® (a filename with an extension
of .FH8 - for version 8), then use them first.
The EPS File Format
If the graphics application you are using cannot read native vector files
the next best thing would be to save them as EPS (Encapsulated PostScript)
files. These are self-contained PostScript files which contain the same
mathematical descriptions as the vector files they are made from. Even
bitmaps can be saved in the EPS file format. EPS files are supported by
most all graphics applications. It is the most portable format for this
reason. It is best to use EPS files for all line art and illustrations
because they can be reproduced at any size or resolution and still display
exactly as they were drawn. Use them wherever native vector files cannot
be used.
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