Reasons to use vector graphics over rasters

Designers have to choose between vector and raster graphics on a daily basis. When should you use vectors or rasters, and does it even matter? There is still a little confusion over what they are...

Vector graphics use geometry to determine shape, colour and form - indeed the word vector actually means line.  All the shapes created in a vector package like Illustrator are based upon mathematical equations and use points, lines and curves to define a shape.  Traditionally, raster graphics (also called bitmaps) use a grid of colour squares to define shape and form and colour - these squares are the pixels.

The most obvious reason to use vectors is scale. Suppose you have drawn an intricate logo and your client needs to advertise on a 20ft long football board. Using rasters you would have to re-draw the whole thing at a massive size, generating a huge file.  How many times have you tried to re-size a raster, only for it to look pixelated and grainy?  With vectors you can just resize your existing artwork and job done - a perfectly clean, high quality graphic the size of a bus! Fantastic.

Speaking of file size, here is another benefit of using vectors. Your vector graphic is drawn using the smallest number of points, whilst retaining image quality. So complex artwork can keep a relatively low file size.

Vector illustrations are made of objects and not of pixels. This has many advantages, one being that it is simple to change an object's colour - just click on it and select your preferred swatch. This is a great option for people who are a bit indecisive about colour – like me. Changing the colour of rasters can be a lot more complicated.

Traditionally, vector packages like Illustrator have been used for mainly for logo design, whilst raster packages like Photoshop are used for website layout design. These days Photoshop supports vectors and Illustrator supports rasters and the lines are becoming blurred between which package to use.

My preference will always be Illustrator, even for web site design because I find it quicker and more fluid to design in. It handles text, specifically paragraphs, far better than Photoshop. You can use paragraph styles, which makes it simple to change your "link" style. You can place photos directly, and it handles bitmap files with ease. And generally I find it creates a cleaner design.

Long live the vector graphic...!