What’s the difference between vector and raster images?

There are two ways of creating images on a computer, vector and raster, and there’s a knack to knowing the difference.

A Raster image of a butterfly
A raster image of the butterfly. In the zoom circle, you can see that the image is made up of square ‘dots’ called pixels

Continuous tone images like photographs are usually raster. Images with large areas of ‘flat’ colour or those created using mathematical equations to define the image are more likely to be vector. Fonts on a computer are also made from vectors.

A vector image of a butterfly
This is a vector image of a butterfly. You can see how the image is made in the zoom circle underneath. The red line is called the path, and the control handles—which control the curve of the path—are also visible.

How does this affect me?

Most of the time, you won’t need to know if an image is vector or raster, but occasionally it can be helpful to know. If you have an image like a logo that needs to be used at a range of different sizes, from say small on a business card, to enormous on a building’s signage, vector formats are best. This is because they can be scaled up or down without losing any definition. Photographic images really don’t look great as vector images though.

What can I do in future?

If we’re creating or sourcing the images for you, you shouldn’t need to worry. If however, you need to supply us with an image, say your logo or a photo for an ad, you will need to know what to send us. We’re always happy to help, so if you’re unsure, please feel free to give us a call and chat it through.

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