What is a BleedBox?

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

The BleedBox

The PDF BleedBox describes the area to which the contents of the page would be clipped during the professional printing process. This includes any bleed regions needed because of physical restrictions of machine cutting etc. Bleed is a "space" that serves to avoid the unwanted appearance of a white border in your printed file. In a printing environment, 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 equal the CropBox.

As an example: In most cases in the printing industry, a bleed of 3 to 5 mm per side is usually required. Specifically, if you have an A4 measuring 210 × 297, a 3 mm bleed enlarges your document to 213 × 300, but cuts to 210 × 297.

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