I Googled and found this page about bleed. It says the following:
The fact that content needs to extend beyond the page boundaries is no excuse for sloppy design. Letting images extend beyond the needed bleed clutters the file, can lead to bloated PDF files and simply looks sloppy.
Point taken that you shouldn’t just leave large graphics unkempt and extended beyond the trim marks willy-nilly because that does seem to clutter the file and be sloppy; and I’m not entirely sure if a desktop publishing program actually cuts off graphics at the edge of its container (for example, in Adobe InDesign, placed images are contained within a bounding box which defines the visibility extent of the images) and embeds only those cuts in the PDF instead of the whole original graphics, but if that’s what it does, then bloated PDFs may be a concern.
That being said, is it really necessary to spend time extending graphics precisely to the bleed marks? Would it be that big a deal if I extend graphics beyond the bleed a tiny bit, like say five milimetres or so? Adobe apps like InDesign or Illustrator actually crop out whatever is beyond the bleed mark anyway on exporting to a PDF, so is it really worth the trouble to be too concerned about bleed when placing graphics? Or is it a problem for other programs upon exporting to PDFs?
Here’s a screenshot of a PDF page exported from InDesign. The original page in InDesign actually has a magenta rectangle extending beyond the bleed mark, but it’s not visible at all here. The cyan rectangle was precisely extended to the bleed mark, and the yellow rectangle to the trim mark.
Objects extending past bleed marks are never really a problem. There’s no such thing as “too much” bleed. Within reason of course. I mean a 6″ bleed would be ridiculous unless it was requested.
However, it never hurts to keep cleanliness in mind while working. Much the same way you can’t work effectively if there are 50 items scattered all over your desk, prepress is made easier if you show a little effort and keep files as clean as possible.
Most high-end apps will crop or truncate objects outside a bleed region. But not all will. And even if you don’t see items outside the bleed area that does not mean those objects aren’t still there and merely hidden via a mask. And extra content, visible or not, always increases file sizes (kb).
So while it’s not imperative that everything stop exactly at the outer bleed area, it’s not a bad idea to keep tidy files whenever possible. If cutting an object at the outer bleed areas mean the object must be manually altered (beyond merely adjusting an object frame), then it may be best to leave the additional object data so as to not alter the on-page, visible portion.
(Note this also goes for all those random things off the page on the pasteboard…. it doesn’t hurt to remove all that working content before generating a press-ready PDF)
Source : Link , Question Author : Vun-Hugh Vaw , Answer Author : Scott