Bleed, Trim and other boxes

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Bleed, Trim and other boxes

Raymond Barkhouse

One of my concern (heh, there's a long list coming) with the current SVG
Print standard is it's lack of elemenents/attributes (in the current
draft on W3C) to define bleed, trim, crop, or other boxes around a page
(or page set).

For those who aren't familiar with bleed and trim I'll give a quick

  A page that has images or colour areas that extend to the outer
  boundary of the finished project will often continue those elements
  outside of the finished area. This is done to allow a margin of error
  when being cut from a press sheet (so you don't little lines of white
  if the guillotine is off).

  Occasionally other information needs to included such as; folding or
  other bindery registration marks; custom colour bars; date, version,
  or other text; etc.

Formats such as PDF handle this with a variety of boxes (see the PDF
Reference 1.6 S10.10.1 "Page Boundaries" or ask and I'll provide an
explanation and example use for each) that are defined relative to the
origin (in PDF it's the bottom left).  These boxes have rules as to how
they fit in each other, eg. a trim box must not exceed the bleed box

So why would we need them?

The first reason is displaying pages to a user vs. displaying them to a
pre-press operator. A user generally wants to see the finished product
so we'd display only the imaging inside the trim box. Pre-press is
concerned with the entire press sheet/printable area.

The second reason and the one I'm more concerned with, is it allows
imposition and other software to automatically lay pages out on press
sheets and generate crop and other registration marks.

I would say this is an essential feature used hundreds of times per day
by any print shop (whether they realise their software uses it or not).


P.S. JDF can take the place of some of the boxes defined in the PDF
spec. if people wish to discuss that.