All about File Types

If you’ve ever wondered what the difference is between a PDF and a PNG or a JPG and an EPS? Read on to find out all you need to know about standard graphic files types and their uses.

Two main colour spaces: RGB & CMYK

There are two main colour modes that documents are saved in: RGB and CMYK. There are others like greyscale, indexed etc but we’ll be focusing on the two most popular.

RGB Colours for screen use

Graphic files that are to be viewed on screens use RGB colours. All colours on monitors, screens, TV’s etc are made of Red, Green and Blue. The RGB colour space is larger than CMYK and allows for more vibrant colours.

Popular file types that support RGB colours: PNG, JPG, PDF, EPS

CMYK Colours for printing

When printing, all colours are made from Cyan, Magenta, Yellow and Black. The CMYK colour space is smaller than RGB and some colours will be reproduce using values as close as possible to the RGB equivalent.

Popular file types that support CMYK colours: JPG, PDF, EPS

Two main types of images: Raster & Vector

Raster Graphics or Rasterized Images

Photography and most realistic images are “raster”. This means that the file is saved as a group of pixels. Each pixel has a colour associated with it. The more pixels the image has, the larger the file size and the clearer the image can be reproduced.

Popular uses for raster images are for on screen and print use where a vector version is not possible.

Dots per Inch refers to the size of the image and how large it can be reproduced.

  • Screens display and require 72 dots per inch to display an image clearly.
  • Printers print and require approximately 300 dots per inch to display an image clearly.

Popular file types that are saved as raster or that support having raster images in them: PNG, JPG, PDF, EPS

Vector Graphics

These are graphics that are made of lines and curves and are saved as mathematical properties. This enables the artwork to be scalable without losing quality. Vector graphics are preferable where possible because they display sharper than raster graphics.

Popular uses for vector graphics are for on screen and print use for logos, illustrations and any graphic elements that require sharp, crisp lines.

Popular file types that are commonly vector: PDF, EPS, SVG