What is Bleed?
Ink (or toner) that is intended to print beyond the final edge of the page to ensure it extends to the edge of the page after we trim it. There is a certain amount of movement when printing on any type of press, therefore you should always create at least 3mm bleed on all edges where printing to the edge of the page is needed. Supplying your job without bleed may result in white lines when we cut it to final size.
How do I add Bleed?
The concept for applying bleed is the same for all desktop publishing software. You will need to extend the object box, whether this be a picture or colour out past the edge of your page. Then, when creating the PDF, you need to set your bleed margins to 3mm. Simply extending your artboard/page area and not extending the picture or colour past the final trim or crop mark is not adding bleed, in fact its just the same as NOT applying any bleed at all!
With Microsoft Word, PowerPoint or Adobe Photoshop you do not have the ability to add the bleed as an export function when creating a PDF. You will need to make your page/image size 6mm bigger at the start. You will then treat the extra 6mm (3mm all round for each edge) as your bleed, which will be removed when we trim your job. As an example, A4 is 210mm x 297mm when trimmed. Your page with bleed will be 216mm x 303mm when supplied, so we can trim the excess off back to the final size.