File Types

Files for printing

1. DPI – Dots per Inch or Pixels

When an item is printed their will often be a significant difference with what you see on your screen. The screen will render an image typically at 300 dpi (dots per inch) and the image will look fine. A laser printer typically works at 1200 dpi. A resolution which is four times greater.

To successfully print your logo on a promotional notebook we cannot use images which have been ‘grabbed’ from web sites or similar – files which are .jpg, .png . tiff or .gif will have insufficient data within them to print successfully. They will appear blurry.

Print files created in design programmes such as Illustrator, In design and Coral with the prefix .ai, .cdr, eps, .svg. are files produced specifically for printing they will be high resolution and will render your logo.

To confuse the issue a PDF can be either high resolution or low resolution – it can be either raster or vector - the printer need the high resolution version. Raster vs vector – what does this mean?

 

2. Raster and Vector

We often define files by the resolution – the number of dots per image. But files can fall into two types. The Raster file is made up of dots or pixels. When enlarged the file will start to blur.

A vector file (ai, eps etc) is actually not made of dots. Rather it is a series of mathematical formulas which determine where the dark and light, and colours appear. You cannot see these formulas but you can tell a vector file because as you enlarge the image the retains its quality.