Crop marks

Crop marks are marks printed in the corners of the paper to indicate where a physical page is to be trimmed to final size. Sometimes it is necessary to add these when preparing a PDF for rendering on a printing press instead of a desktop printer. There is no standard means for specifying crop marks in the XSL-FO 1.0 specification, but it is a feature that some XSL-FO processors offer as an extension.

If you are using an XSL-FO processor from Antenna House or RenderX, then there are several stylesheet parameters you can use to control crop marks.

<xsl:param name="crop.marks" select="1"/>
Turn on crop marks. The default value is zero (off).
<xsl:param name="crop.mark.width">1pt
The thickness of the crop mark lines. The default is 0.5pt.
<xsl:param name="crop.mark.offset">0.5in
The distance from the trimmed page edge to the outer end of a crop mark. The default value is 24pt.
<xsl:param name="crop.mark.bleed">0.25in
The distance from the trimmed page edge to the inner end of a crop mark. The default value is 6pt. This is the amount of the crop mark line to hide, in order that it not show by accident.

The trimmed page edge is the page size specified by the stylesheet parameters page.height and page.width. The crop marks are drawn outward from those corners. If you specify a crop.mark.bleed of 0pt, then the two crop marks will meet at each page corner, extending outward from the corner to a distance equal to the crop.mark.offset. However, it is not a good idea for the crop marks to meet at the corner, because if a sheet is positioned slightly off at trim time, part of the crop mark will show. If you specify a crop.mark.bleed distance, then that much of the line will be hidden, so the crop marks will no longer meet at the corner. It shortens the displayed crop mark line by that amount, without moving its outer end.

Keep in mind that if you want to the crop marks to show on a desktop printer, you have to print onto a sheet of paper large enough to accomodate both your page size and the crop marks. If you want an accurate printing, then turn off the page scaling that the PDF browser might apply in the print dialog box.

Note that the Document Properties dialog box in a PDF viewer will show the page size including the crop marks. That is, if you specify page.width="6in", page.height="8in", and crop.mark.offset=".5in", the the document properties will show the page size as 7 in by 9 in.