What Is a Vector File?
Many popular, consumer graphic-design applications offer professional-grade tools and creative features in an interface even a novice user can navigate. To use these tools to their fullest, it's important that you understand the difference between graphic formats and how each is implemented into visual design.
Vector Versus Raster
In the world of digital images and design, there are two graphic formats: vector and raster. Vector graphics, which are the preferred format for files that are not photographs, are made up of points, lines and curves -- or paths -- containing colors, gradients and other editable effects. Raster graphics or bitmap images, on the other hand, are the preferred format for photographs and are made up of thousands of squares of color -- called pixels.
As far as your computer is concerned, the points and paths in vector graphics are nothing more than code written in a programming language called PostScript. Early computer-based graphic designers created artwork displayed on the screen by manually typing this programming language into a text file. Soon, Adobe's Illustrator software presented the user with a simpler, graphical interface -- with on-screen drawing functionality and a palette of tools -- that automatically generated the programming language in the background.
A handful of mathematical shapes -- called primitives -- make up all vector graphics. An illustration of a daisy, for example, contains a number of smaller, individual parts: the triangles and diamonds of the leaves, the rectangle of its stem, and the circles and ellipses making up its petals and center. Each shape is assigned a plane and given an editable stroke -- or line -- color, thickness and fill. Unlike the boxy pixels of a raster photo, which become blurry when enlarged, vector graphics remain smooth when scaled up or down.
In addition to high-quality magnification, vector graphics offer a few other helpful benefits. They support the use of spot colors, which are solid colors that can be calibrated to display and print consistently using any commercial printer. Because each point has a definite position on the X and Y axes, a vector graphic can also be rotated, moved, stretched and skewed. Additionally, support for transparency means your vector graphics can be cleanly overlapped without having to deal with unsightly backgrounds.