No idea what people are going on about when they talk about raster and vector based graphics, pixels and paths? Let me explain…

Vector…

Ok so lets start with Vectors, probably the hardest one to get your head around, when we talk about vectors we are talking about lines and curves, artwork made from anchor points in Illustrator or InDesign – basically it is artwork that is created from scratch in a design programme, artwork that is based on paths and curves has no resolution information, there are no pixels per inch or dots per inch it is all scaled from the path that is drawn.

So when we scale vector artwork the software increases the size on a mathematical grid so we loose absolutely no quality at all, this is why all companies should have a vector version of their logo, they can then put it on a business card and also scale it up on to the side of a lorry with no loss of quality and keep absolute consistency with all its branding.

Examples of Vector files are Illustrator (.ai) Encapsulated Post Script (.eps) and Portable Document Format (.PDF)

So to summarise any company logo or any graphics you want to scale up and down and keep a consistent quality use a vector format, although there are limitations to how photo realistic we can get vectors so we still need photographs also known as Raster based artwork…

Raster…

Raster is anything pixel based, when we look at any image and zoom in on it we will start to see dotts little tiny squares that the image is made up of, these squares are measured by how many there are per square inch of the image. As a rule of thumb a good quality print resolution is 300 pixels per square inch so this is what we aim for but if we double the size of the image we half the resolution, so there fore all raster/pixel based images have a limit on how much they can be scaled before you start to loose quality.

When we make a raster or pixel based image too big we can start to see the squares that it is made up of, this is when the image has become what we call ‘Pixelated’.

Examples of Raster based files are Joint Photographic Expert Group (JPEG) Tagged Image File Format (TIFF) Portable Network Graphics (PNG)

I hope this has helped to make things a little clearer.

Mark Williams is the Director of Creative Studios Derby LTD, the East Midlands largest and most experienced Adobe training centre. If you need help learning any software from the Adobe Creative Suite, then contact us.

We regularly run Adobe InDesign Training Courses and Adobe Illustrator Training Courses from our state of the art studio in Derby.