Digital files usually fall into two categories: vector and bitmap. Vector is the ideal format for line art and logos. In this type of file, the artwork is made of paths. Each path is a connected series of points. Path construction allows for the easy alteration of lines in the image as well as easy scaling of images without loss of image quality.
Vector art requires software that allows for the editing of paths as well as user proficiency in working with paths. Common programs for creating and editing vector art include Adobe Illustrator, Macromedia Freehand, or CorelDRAW. Please note that there may be some compatibility issues when importing vector art files into some programs in a PC or non-postscript enabled device. Some common file formats that retain vectors are Illustrator, Freehand, CorelDRAW, EPS, PDF, and WMF.
Bitmap formats are most common in scanned arts. In these files, the artwork is comprised by a large number of dots or pixels. The assignment and number of these pixels is directly related to the resolution of the artwork. Because of this, when resizing bitmap images (enlarging in particular), the edges become jagged. With this format, it’s imperative to scan at a proper resolution —120 DPI is ideal for line art. Low resolution leads to poor image quality and a large amount of cleanup time to fix the image to make it workable. This format is highly compatible amongst software and cross platform. If created at the proper resolution, this format provides excellent image quality. Common formats include Photoshop, TIF, PNG, BMP, JPEG, and GIE.
—Michael Sullivan, IKONICS Imaging