"Bleed" and "Trim Allowance" group
The purpose of the bleed and/or trim allowance is to avoid unprinted (white) margins on the cut edges when cutting the printed pages. To do this, the page contents are printed larger by a certain area than the basic page size (e.g. A4) so that the cut edge is within the printed area.
The "Bleed" dimension determines the maximum width that will still be printed outside the page trim box. For example, if a bleed of 3 mm is set, a border 3 mm wide will be printed outside the page trim box, even if a larger content area outside the trim box is defined in the PDF.
You can define a dimension for the bleed in the "Bleed" box.
The trim allowance defines how much larger the folding sheet is than the page trim box. It may be necessary, for example, to trim the size of the pages to the size of the folding sheets before folding, then fold the pages, and finally to trim the pages to the size of the trim box. For example, if a bleed of 3 mm has been defined for a page in A4 format and the "Trim allowance" option is set to "Automatic", the bleed box is increased in size proportionally so that its size is 6 mm wider and 6 mm higher than the A4 format. The page trim box is set precisely to A4 size and accordingly the page can be trimmed to A4 format.
Note: To prevent white margins from occurring during trimming, the contents of the page must be slightly larger than the page trim box. You can make sure of this as follows:
·The page trim boxes are correctly defined in the edited PDF documents or
·the page trim boxes are scaled, for example, to 98% and "Page Policies" is set to "Center" (see "Trimmed size" group).
You can use the Prinect PDF Toolbox, for example, to define or modify the trim boxes in the input PDF documents.
Note: Remember that not all digital presses can print without margins (e.g.Heidelberg Versafire models).
The trim allowance is used to specify the increase in size of the folding sheet compared to the trim box. You can enter separate values for the vertical and horizontal trim allowance. This is possible only if the "Automatic" option was disabled. Remember that you can edit the height proportions of the pages if different values are entered for the horizontal and vertical trim allowance.
"Automatic" option
When this option is disabled, the bleed box (size of the folding sheet) is exactly the same size as the trim box (this is set in the PDF document).
When this option is enabled, the size of the folding sheet is set automatically to have as few cuts as possible when cutting the folding sheets.
In general, it is advisable and sufficient to activate the "Automatic" option.
Tips:
If a bleed does not appear in the preview as expected, or no trim allowance is visible, this may be due to the following reasons:
•No trim boxes are defined for the PDF pages of the source documents or the bleed boxes are smaller than or the same size as the trim box.
Remedies: Create or correct the required trim boxes in the document PDFs (e.g. with PDF Toolbox).
•No trim allowance is defined in the "Trimmed size" area of the "Digital Printing" window.
Remedy: Define trim allowance for the pages (e.g. by checking the "Automatic" option).
•The value for the bleed is set to "0" in the page parameters of the "Digital Printing" window.
Remedy: Enter a bleed greater than "0" or check the "Automatic" option.
Note: If you need to revise the input documents, for example, to correctly define the page trim box or bleed box or to scale the page content, you can define the appropriate settings in the Qualify sequence (see "Pages / 1ups" tab) or use the tools included in Prinect PDF Toolbox. The PDF Toolbox is an Acrobat plug-in and is installed along with the Cockpit software. Document editing with the PDF Toolbox is done outside the Prinect Manager workflow.