A PDF page may be prepared either for a finished medium, such as a sheet of paper, or as part of a prepress
process in which the content of the page is placed on an intermediate medium, such as film or an imposed
reproduction plate. In the latter case, it is important to distinguish between the intermediate page and the
finished page. The intermediate page may often include additional production-related content, such as bleeds
or printer marks, that falls outside the boundaries of the finished page. To handle such cases, a PDF page may
define as many as five separate boundaries to control various aspects of the imaging process:
GemBox.Pdf (in GemBox.Pdf.dll) Version: 10.0.35.1002
public enum PdfPageBoundaryType
Public Enumeration PdfPageBoundaryType
The media box defines the boundaries of the physical medium on which the page is to be printed. It may
include any extended area surrounding the finished page for bleed, printing marks, or other such purposes.
It may also include areas close to the edges of the medium that cannot be marked because of physical
limitations of the output device. Content falling outside this boundary may safely be discarded without
affecting the meaning of the PDF file.
The crop box defines the region to which the contents of the page shall be clipped (cropped) when
displayed or printed. Unlike the other boxes, the crop box has no defined meaning in terms of physical
page geometry or intended use; it merely imposes clipping on the page contents. However, in the absence
of additional information (such as imposition instructions specified in a JDF or PJTF job ticket), the crop
box determines how the page’s contents shall be positioned on the output medium.
The bleed box (PDF 1.3) defines the region to which the contents of the page shall be clipped when output
in a production environment. This may include any extra bleed area needed to accommodate the physical
limitations of cutting, folding, and trimming equipment. The actual printed page may include printing marks
that fall outside the bleed box.
The trim box (PDF 1.3) defines the intended dimensions of the finished page after trimming. It may be
smaller than the media box to allow for production-related content, such as printing instructions, cut marks,
or colour bars.
The art box (PDF 1.3) defines the extent of the page’s meaningful content (including potential white space)
as intended by the page’s creator.