The most important distinction
between file types is between vector and bitmap graphic file
formats.
Vector images are made up of lines and filled areas only,
which are mathematically drawn and calculated (hence the term vector) by
the software you use. They can be
stretched in size without losing any clarity or sharpness. Because of their
mathematical origins, vector images are readily scaleable without
distortion.
Bitmap images are composed of lots of small dots. This lends itself to photographic or
artistic effects because color gradations can be made very smooth in a bitmap
format. However, bitmap images lose their clarity when they are increased in
size because the dots get bigger. Take an image that's 10 pixels wide by 10
pixels high, stretch it to 100 x 100 pixels and it looks like it's made of big
squares.
Which file types are vector,
and which are bitmap?
Here is a table of common file types.
The associated filename extensions are listed in
parentheses:
|
Vector (use AdobeIllustrator) |
Bitmap (Use Adobe
Photoshop) |
|
Illustrator
(.AI)* PostScript
(.PS)* Windows Meta File
(.WMF) Flash Movie (.FLA,
.SWF)** |
Graphic Interchange Format
(.GIF) Joint Photographers Expert
Group (.JPEG, .JPG) Tagged Image File Format
(.TIFF, .TIF) Encapuslated PostScript
(.EPS)* |
What are these particular
file types used for?
|
File
Type |
Vector/Bitmap |
Use/Function |
Compatibility |
|
Windows Meta File
(.WMF) |
Vector |
Clipart |
Print (can convert to
web) |
|
Graphic Interchange Format
(.GIF) |
Bitmap |
Web animations |
Web |
|
Joint Photographers Expert
Group (.JPEG, .JPG) |
Bitmap |
Web graphics |
Web
|
|
Tagged Image File Format
(.TIFF, .TIF) |
Bitmap |
Photos |
Print (can convert to
web) |
|
Flash Movie (.FLA,
.SWF)** |
Vector |
Web animations and
interactive controls |
Web |
Here’s a table of pros and cons
for using Vector Art vs. Bitmap Art:
|
|
Vector/Line
Art |
Bitmap |
|
Scalability |
Scales without
distorting |
Distorts when
scaled |
|
Relative file
sizes |
Usually small
files |
Usually large
files |
|
Typical Color
Use |
Fewer number of
colors |
Greater number of
colors |
|
Use in
Print |
Best for text and
illustrations |
Best for
photos |
|
Smoothness of
lines |
Always very
smooth |
Can be fairly smooth when
resolution is very high |
|
Smoothness of color
gradation |
Gradients not as
smooth; |
Gradients are
smooth; |
Other Vector Formats
Many websites use Macromedia Flash to create web site animation and interactive controls. The advantage of using Flash to create interactive “movies” in .SWF format is that all of its graphics are generated as vector artwork, and the Flash player plug-in which installs itself into the user’s browser is able to interpret a Flash “movie” and render it very cleanly and accurately on-screen. Flash “movies” are also scaleable depending on the browser window, and will scale in the same manner as vector art.