The Postscript language was developed to allow variable data files such as photographs to coexist with sharp line-art graphics like type in the same file. In printed works, this is what creates high resolution lines and logos that are infinitely scalable, as well as large image files in an efficient manner. In large format graphic work, the formats may be used in unison or separately to take advantage of the outline properties of vector graphics. Here’s an explanation of the two image kinds and below you’ll find some tips on setting up cut paths for your vendors.
Photographic or raster images use information cells called pixels to create every inch of graphic as rows of dots. Measured in dots per inch, i.e., 100 dpi has 100 lines by 100 lines of pixels of information in every inch of your graphic. Enlarging these files too much can result in unacceptable quality. Think of a screen door, the holes being your pixels, if you enlarge the door with the same amount of screening the holes will get larger, and more noticeable. If you enlarge a raster image file, the pixels become more obvious and the image detail becomes degraded. This is a gradual effect and has a varying degree of acceptability, however, staying with recommended resolution values will avoid disappointing results. Images with varying shading are generally raster images.
Line art such as type, frames, strokes and boxes are considered vector images. Vector image files are 2D graphics made up of plot points, lines and curves and fills. These files ensure that you can enlarge an image without image loss or degeneration regardless of how large you request, because they are simply made of coordinates, not individual dots. Vector files also include the the plot points, lines and curves that your vendors software will require to create cut paths for your custom shaped project, however they may need to be merged or welded into one shape for a proper cut path, see below for instructions.
Vendors may require a vector file for some of your projects depending on the process, this is especially true if you are ordering cut vinyl or custom shape cut graphics. The vector file request may require that all graphics within the file are made up of vectors such as a logo or text, or that you create a vector cut path around your raster images for a shape or contour cut graphic.
Note: Special effects such as glows and shadows applied to vector graphics will always be rasterized by your software and may need to be removed.