Vector graphics are made up of lines, curves and shapes. Think of a vector as a series of dot-to-dots joined up to create paths. The shapes created by the paths can be coloured in, scaled up and the paths themselves can be later manipulated.
Raster graphics are made of pixels – a grid of tiny squares that can be coloured in. All photographs are raster images, and if you zoom in close enough you should be able to start seeing the pixels that create them.
Let’s take a look at Disney’s logo to demonstrate the difference, visually:
The purposes of the two file types are quite different. Depth, tonal variety and subtle colour gradients are much easier to achieve in raster form, whereas a crisp type based geometric design suits the vector format.
Nearly all logo files are vector graphics.
The benefit of a vector graphic is that it is infinitely scalable. You could expand a design to fit the side of a building, and it wouldn’t loose quality. This makes it the perfect option for a logo file. When you scale a vector image it will maintain a smooth quality whereas a raster image will start to look fuzzy.
They are also device-independent which means your logo will still look good on low resolution screens and printers.
There are however, exceptions. On occasion, organisations want photography based logos, think of the Basset Hound of Hush Puppies. Or highly textured logos like Disney’s Frozen. At a small scale, these can be highly effective. But it is worth having a backup vector file for large scale formats, or risk creating an unwieldy sized logo that is difficult to manage.
As vector files are simply a mathematical formula it means the file size is pretty small. Whereas a high quality raster file would need a very high resolution (more pixels = higher resolution) to retain its integrity at a large size, which results in a very large file type.
Whilst the raster format is the natural format used within photography and most digital applications, a vector format can only be created using specialist software such as Adobe Illustrator or CorelDRAW.
File Formats for Raster Images
- .jpg (Joint Photographics Expert Group)
- .png (Portable Network Graphic)
- .tiff (Tagged Image File Format)
- .pdf (Portable Document Format)
- .psd (Adobe Photoshop Document)
File Formats for Vector Images
- .ai (Adobe Illustrator document)
- .eps (Encapsulated PostScript)
- .svg (Scalable Vector Graphic)
- .pdf (Portable Document Format; only when saved from vector programs)