What is a BleedBox?

A PDF describes the content and appearance of one or more pages, and also defines the physical size of those pages. There can be up to five different size definitions in a PDF: MediaBox, CropBox, BleedBox, TrimBox and ArtBox. These are called the page boxes or boundary boxes. PDF boxes describe the page geometry of a PDF. They are used frequently in the printing industry.

The BleedBox

The PDF BleedBox defines the area where the page content is trimmed during professional printing. This includes any bleed areas needed because of physical limits of machine cutting, etc. Bleed is a "space" that helps prevent unwanted white borders in your printed file. In a printing workflow, the BleedBox is always larger than the Trimbox. It contains information about the bleed frame, which defines the size of the final format plus the intended trim. If not set, the BleedBox will be the same as the CropBox.

For example: In commercial printing, a bleed of 3 to 5 mm per side is usually required. If you have an A4 page measuring 210 × 297, a 3 mm bleed enlarges your document to 213 × 300, but it is trimmed back to 210 × 297.

Read more about the other PDF boxes in the following article: What are PDF boxes?