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PDF문서의 MediaBox, CropBox, ArtBox에 대하여

[출처:http://www.prepressure.com/pdf/basics/page_boxes]

The PDF page boxes: MediaBox, CropBox, BleedBox, TrimBox & ArtBox

A PDF describes the content and appearance of one or more pages. The exact size of that page is not as straightforward as you might think. There can be up to 5 different descriptions in a PDF that relate to its size. These are called the page boxes:

  • The MediaBox is used to specify the width and height of the page. For the average user, this probably equals the actual page size. For prepress use, this is not the case as we prefer our pages to be defined slightly oversized so that we can see the bleed (Images or other elements touching an outer edge of a printed page need to extend beyond the edge of the paper to compensate for inaccuracies in trimming the page), the crop marks and useful information such as the file name or the date and time when the file was created. This means that PDF files used in graphic arts usually have a MediaBox which is larger then the trimmed page size. The MediaBox is the largest page box in a PDF. The other page boxes can equal the size of the MediaBox but they cannot be larger.
  • The CropBox defines the region to which the page contents are to be clipped. Acrobat uses this size for screen display and printing. For prepress use, the CropBox is pretty irrelevant. The GWG industry association recommends not to use the CropBox at all.
  • The BleedBox determines the region to which the page contents needs to be clipped when output in a production environment. Usually the BleedBox is 3 to 5 millimetres larger than the TrimBox. It is nice to know the size of the BleedBox but it isn’t that important in graphic arts. Most prepress systems allow you to define the amount of bleed yourself and ignore the BleedBox. By default the BleedBox equals the CropBox.
  • The TrimBox defines the intended dimensions of the finished page. Contrary to the CropBox, the TrimBox is very important because it defines the actual page size. The imposition programs and workflows that I know all use the TrimBox as the basis for positioning pages on a press sheet. By default the TrimBox equals the CropBox. When creating PDFs that are PDF/X-1a or PDF/X-3 compliant it is a requirement that the MediaBox, TrimBox and BleedBox are properly defined in the PDF.
  • The ArtBox is a bit of a special case. It can define a region within a page that is of special interest. It is rarely used by applications. One way in which it can be used is to handle ads: on a PDF of a page on which there is an advertisement, the ArtBox can define the size of that ad. This allows you to place that PDF on another page but only use the ad from that PDF.

How to see the presence and/or size of the page boxes

A PDF always has a MediaBox definition. All the other page boxes do not necessarily have to be present within the file.

If you crop pages in Adobe Acrobat 6 and later, the window that is shown displays the size of the various box sizes. Another option is to use the Preflight function in Acrobat Professional (version 6 and later). The pages boxes are shown in the Page information section.

There are a number of plug-ins that are a bit more user friendly than the Acrobat functions. I personally love the DocuBox plug-in which is a part of Agfa’s Apogee Prepress workflow.

How to change page boxes

You can use the Crop Pages tool in Acrobat Professional to change the page boxes. A number of plug-ins offer more sophisticated control. Enfocus PitStop isn’t too bad but again I prefer the Agfa DocuBox plug-in. If you know about a good plug-in, add a comment to this page!

Do I even need to worry about all these boxes?

In the past: YES. Older applications did not define the trim box properly, forcing most prepress operators to center pages and hope everything worked out fine (which it usually did, by the way).

Nowadays applications are PDF-aware enough to get things right from the start. Take Adobe InDesign for example:

  • BleedBox information is sourced from the bleed settings in the marks & bleeds section of the print dialog box.
  • The TrimBox is taken from the document setup.
  • The MediaBox size is defined by the media size to which you print. If the “paper”-size width and height are set to automatic, the MediaBox size will be equal to the BleedBox size.
  • The CropBox size is set to be the same as the Media size.

I want to see the finished trim size of a PDF

To view a PDF at it’s finished (trim) size, set the CropBox to match the TrimBox. Some systems do this by default. This has users who are not familiar with PDF worry if there is any bleed in the document. They do not realise that there may be information available which simply isn’t visible on-screen. Acrobat plug-ins such as Enfocus PitStop allow you to alternate the PDF view between TrimBox and MediaBox.

Errors referring to the BBox

Within PDF files there is another box, the bounding box or BBox, that is used. The bounding box is a rectangular frame that determines the dimensions of an object (such as a graphic, font or pattern) that is placed inside a PDF document. As such, this box has nothing to do with the page boxes. Due to bugs in PDF creation or viewing tools,  errors that refer to a BBox may pop up when an application processes a PDF. A typical example is ‘The Font “ArialMT” contains a bad /BBox’.

22 Responses to “The PDF page boxes: MediaBox, CropBox, BleedBox, TrimBox & ArtBox”

  1. Frusterated User says:

    Why the fucking hell can’t I permanently and completely remove everything that lies outside one of these boxes?????? Is there any other way to arrive at the same result??????

    • Laurens says:

      You can do this with an Enfocus PitStop action list. Using this Acrobat Professional plug-in you can select all objects that are outside a selected page box and have them deleted. There may be other plug-ins that offer the same function but I only have PitStop at my disposal.

  2. Grateful user says:

    Thanks for this very clear, informative article!

  3. Mike says:

    Thanks for the info. Let’s see if the Trimbox, plus specific instructions will allow Staples / Business Depot to print / trim my job correctly for me!

  4. The only way to get Staples/Business Depot to print your job correctly, is to take is elsewhere.
    I have ‘never’ had a good experience at Staples. Each time I vowed to never return, then I needed a job done quickly and they were the only option. And every time they took that new job as another opportunity to wreck their own reputation.
    If it’s worth printing, it’s worth finding a real printer.

  5. Claire says:

    Is there any way to print a PDF from Acrobat Professional or Pitstop that shows all the boxes. I want to have a hard copy proof that shows the bleed box and Trim box so I can make sure all my bleeds are accounted for. Yes you can see all of it on screen but if you want to pass it around the office to get sign off, the screen doesn’t always work. Is there another plug in that can do this if the above can’t?

  6. Rajesh Kumaran says:

    Hi, I have apogeex docubox manager.
    Can I create trim marks and bleeds with apogeex docubox in apdf file.
    Please tell me how?
    Regards
    Rajesh

    • Laurens says:

      about ApogeeX Docubox: I am also running it on my system and it is a great tool but you cannot use it to add trim marks. ApogeeX itself is capable of doing that, using for instance the border marks.

  7. DingoDog says:

    a pdf having these box sizes:

    Page size: 420 x 595 pts
    MediaBox: 0.00 0.00 420.00 595.00
    CropBox: 0.00 0.00 420.00 595.00
    BleedBox: 0.00 0.00 420.00 595.00
    TrimBox: 0.00 0.00 420.00 595.00
    ArtBox: 0.00 0.00 420.00 595.00

    is wrong regard to trimbox? it needs to be corrected? defining the trimbox is possible in Linux? how?

    • Laurens says:

      It is perfectly normal that the trimbox has the same size as the page size. Usually the mediabox and bleedbox are bigger than the page size but if you are creating PDF files from a wordprocessor or other office application, it is normal that these applications aren’t aware of the concept of bleed.
      Qoppa PDF Studio runs on Linux and allows you to change the page boxes. I have never used the application myself and don’t know how good it is.

  8. Dear Colleagues:

    Please help to resolve the prepress issue. I need to prodice all book files with a PDF/X-1a 2001 setting. When I placing this setting in Acrobat 9 befor distilling or re distilling a word or pdf file I very often receive an error message [Violation] Both TrimBoxes and ArtBoxes were found on the following
    > pages:
    and there is usually 1 problem for each page.

    Please adivise is it possible to get rid of this problem changing the setting in Acrobat 9 or I need to run these files throung a PitStop to resolve this problems

    Igor Oleynik
    Washington DC

  9. Rajesh Kumaran says:

    Hi, when I visit this web last year thing are not clear. Now it seem ok to understand preepress guys. Now I’m using docubox manager properly.

    Thanks

    Rajesh Kumaran

  10. Jim says:

    Thanks for this great article.

    I’m searching for a Unix utility to list PDF box sizes. Any recommedations?

    Can the Art Box be printed from Acrobat or another utility or plugin?

  11. Lorraine says:

    There does not appear to be a way to set the art box when exporting a pdf from InDesign. In a pure pdf workflow, our equipment acknowledges trim box & crop box for easy bleed setup, but the art box is also recognized and clips the image to trim size. No options in Preferences that I can see to set the art box for all documents.

  12. Frank Tol says:

    As a bookprinter, we regularly receive updates of a PDF. Very often the trimbox of the one page that is new has a very different size. Are there ways to get a warning in the creation process or a tool that will automatically adjust the one page trimbox in line with the other pages?

    • Laurens says:

      Some prepress workflow systems can point out inconsistencies in the page boxes of all the PDF files of a job.
      I am not aware of any tools that can do this in the PDF creation phase. It also seems difficult to do since an application cannot know that for instance those 4 InDesign PDF exports created by 2 different designers are actually part of the same publication. Nothing stops a publisher from preflighting all their outgoing PDF files agains a fixed page size.
      Maybe other visitors to this page can point to possible solutions.

  13. Netz says:

    Hi,
    I loaded a PDF file using Apache PDFbox jar. this PDF exists without any boxes defined (media, crop, etc). How can I tell the page dimensions?
    Thanks a lot.

    • Laurens says:

      Every PDF I have ever seen had a Media Box. I haven’t checked the PDF spec from Adobe to see if this is actually mandatory. It might be a good idea if you look at those specifications (a free download from Adobe). Maybe you’re getting PDF files that are not up to spec.

  14. If you have PDF with prepress cropmarks and want to get rid of it:
    1. Open PDF in Acrobat Professional
    2. Open Document -> Crop pages dialog
    3. Select TrimBox from dropdown
    4. Write down margin values in “Margin Controls”
    5. Select CropBox from dropdown
    6. Enter margin values in “Margin Controls”
    7. Select “All” in page range
    8. Click OK

    Thanks for the article!

  15. Tim says:

    Netz, Laurens: MediaBox is indeed required. However contrary to this article, I have found a PDF with a cropbox larger than the mediabox:

    /CropBox[0 0 595 842]
    /MediaBox[82.5 90 512.5 750]
    /TrimBox[82.5 90 512.5 750]

    I guess this means it has no effect.

    My question is: Which box does Adobe reader use to decide how much of the page to display. My guess would have been TrimBox, which defaults to the value of CropBox, which defaults to the value of MediaBox, but this doesn’t seem to be the case.

  16. Katie says:

    Is it possible to use the crop controls to adjust registration for back to front printing? Our printer is slightly off, so I’m trying to use the crop Odd pages to shift the image slightly on the paper to compensate. What puzzles me is that if I set the crop/trim to .0623 and then set to zero, when I open the Crop Pages again, it has reverted back to .0623.

  17. Katie says:

    I was able to manipulate the image by using Crop and Trim both on just the odd pages. The Even page still shows .623 crop but it does not show up when I view the pages.