Monday, October 17, 2005

Vectored Artwork

For the purpose of imprinting your logo or artwork on a promotional product, you will need a computer graphic file with a vector image. Most of the vector files will be CDR (CorelDraw) or AI (Adobe Illustrator) or FH8 (Macromedia FreeHand) or can also be an EPS (Encapsulated PostScript) file. However, a raster image (bitmap) can also be saved as an EPS and cannot be used (see why below). JPEG and GIF images are also bitmap and we cannot use them.

If your logo or artwork is not a vector image, it must be recreated as a vector image by an artist.

VECTOR vs RASTER GRAPHICS
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.

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. 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 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.

1 comment:

Mark Sicignano said...

Here is a tutorial for those that might be inclined to convert bitmaps to vector using Photoshop.

http://www.designsbymark.com/freetips/ps/movies/convtovector.mov

I believe that the designsbymark.com site may be shutting down, so I don't know how long that movie will be available.