Generate bleed from page content: updated in pdfToolbox 12

With pdfToolbox, you are able to create bleed

  • in a number of ways:
    • by mirroring page content from the edges of the page (in the form of pixels or in the form)
    • by mirroring all objects of the current page content and clipped to the area needed for the bleed
    • by repeating pixels at the edges of the page
    • by stretching the content at the edges of the page
    • in all cases bleed may be generated
      • just for the edges (and not for the corners)
      • for the edges and for the corners
  • in a number of color spaces, including
    • the color space defined in the OutputIntent (if present; otherwise CMYK is used)
    • CMYK ("ISO Coated v2"); for the generated bleed area, any spot colors will be converted to CMYK
    • CMYK ("ISO Coated v2") + spot colors
    • grayscale; for the generated bleed area, all non-grayscale colors will be converted to grayscale
    • sRGB; for the generated bleed area, all colors that are neither sRGB nor plain RGB will be converted to sRGB

Geometry aspects for the bleed generation – on which sides of the page(s) to generate, based on which page edges, how much of the current page content to use, how much bleed to create – can be configured very flexibly.

How to create bleed by mirroring page content at the edges of the page

The following section contains a tutorial that shows how to generate bleed by means of mirroring the page content at the edges of the page.

Open the sample PDF and the "Generate bleed at page edges" dialog

Open the attached PDF "Bleed_Demo_file_1.pdf" (or your own document) and create a new Fixup.

  • Fixup category: Pages
  • Fixup type: Generate bleed at page edges

Configure the "Generate bleed at page edges" fixup

1. In the "Method" drop down list, select the desired method ("Mirror as image (edges and corners)" is used in our example here).

Method Explanation

Mirror as image (edges)

OR

Mirror as image (edges and corners)

Using this method, the colorspace for the created image needs to be defined. 

Repeat last pixel as image (edges)

OR

Repeat last pixel as image (edges and corners)

Using this method, the colorspace for the created image needs to be defined. 

Mirror page objects (edges)

OR

Mirror page objects (edges and corners)

A colorspace is not defined, the mirrored page content simply keeps its existing colorspace(s).


Stretch border area as image (edges)

OR

Stretch border area as image (edges and corners)


Using this method, the colorspace for the created image needs to be defined.

2. In the "Colorspace" drop down list select "CMYK and spot colors"

Following settings for the "Colorspace" parameter are available:

  • Use OutputIntent (CMYK will be used if no OutputIntent is present)
  • CMYK
  • CMYK and spot colors
  • RGB (sRGB IEC61966-2.1)
  • Grayscale

3. Click on the edit button "Parameters" button to configure the desired bleed geometry in a separate "Generate bleed at page edges parameters" dialog:

Generate bleed at page edges parameters

  1. Create bleed at: Which page geometry box to consider as the current edges of the page; usually the TrimBox is used here, if present, or the CropBox, if the presence of a correct TrimBox is not to be expected;  it is also possible to define a "CustomBox" in which case the four parameters just below this option are enabled, and suitable values can be entered.
  2. Bleed width: The "amount" of bleed to generate.  
  3. Offset to box: How much the source area for bleed generation – in this example the TrimBox –  shall be adjusted, such that edges are ‘nudged’ away from the border of the page (per selection in the "Create bleed at" option). Negative values move the edge towards the center of the page, positive values move the edge outside of the page. This is often used to accommodate pages where the page content ends slightly before the TrimBox edges (in many cased by just a pixel row – which would otherwise remain visible and create a noticeable white line once the bleed is generated)

Click OK, save the Fixup, and execute the fixup.

Review the processed PDF file in pdfToolbox

5 mm bleed is added on all sides.

Different set of parameters for "Stretch border area as image"

In case the "Stretch border area as image" mode (which has been invented with pdfToolbox 12) is used for generating bleed from page content, two additional parameters are shown that need to be configured:

  1. Source width: Width of area just inside TrimBox to be used for stretching this area into a larger area such that bleed 'emerges'. Both this source area as well as the bleed are (per "Bleed width") will represented in the form of an image.
  2. Stretch factor: Factor for the exponential function used to compute the increasing stretch effect. The same stretch factor is used for all four sides. The content in the source area is 'stretched' to a varying degree: the closer to the page edge, the higher the degree of stretching. The slope of the underlying 'stretching curve' is controlled by the stretch factor.

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