December 7th, 2010
Let’s start by defining what a vector is.
In its simplest form a vector is a representation of an image using lines, points, and curves. The construction of vectors is based on mathematical calculations. What that means is with a vector there is no defined size, therefore pixelation will never occur. Vectors can scale up and down to any size and remain the same quality. The mathematical equations allow this to happen.
Raster, or sometimes called bitmap, is just the opposite. Raster is a specified size and is based on pixels. This means that when a raster image is enlarged it will become pixelated.
Pixelation is the blurriness or distortion that occurs with an image is stretched larger than its native size. Say you have an image that is 100×100 pixels, that is the native size. When you take that image and enlarge it to 500×500 pixles the computer has to fill in the gaps. In doing this the image loses clarity and becomes pixelated.
Vector and raster both have their place and purpose. Although not exclusively, vector is often used for print. It is great for print because of its scaling capabilities. Logo design should always be done in vectors. If you are having marketing pieces printed be sure to use a vector logo to ensure it will come out crisp. Raster is beneficial when dealing with images of an organic nature, such as photos. The complex calculations would be too intense to display in vectors. Raster is also often used for web. With web design there is no need to be scaled larger than the biggest screen size so raster is perfect.