There’s a fair amount of lore to do with bleeds and the edges of printed pages that I fear is being lost in our magnificent digital age. I wanted to run through some of it, and if I leave anything out or don’t explain something properly, by all means make suggestions or ask questions in the comments. I’m sure this will seem very basic to many of you, but judging from the files I’m seeing, it should be helpful to some if I review the fundamentals.
The way things work in offset and digital printing, when a graphic element goes all the way to the edge of the page, it has to bleed. This means that the element really has to go past the edge of the page (in InDesign or QuarkXPress), and then after the piece is printed and the pages are folded and trimmed, the part that goes past the trim edge (called the bleed allowance) is trimmed off. Because the trimming process isn’t absolutely perfect, if you didn’t have a bleed allowance, on some copies you’d end up with white lines along the edges of trimmed pages with elements that were intended to go all the way to the edge.
The industry standard bleed allowance is 0.125 inch. (For you points-and-picas nerds, that’s p9). If you’re working on, say, a really large poster or you know your pages are going to be output at a reduced size (for example, 8.5 x 11 inches in InDesign but destined to be output so that the height of the finished piece is 10.875 inches), you should consider using a larger bleed allowance. If in doubt, consulting with your friendly printer’s rep is always a good idea.
Situation Normal …
So how does this all play out in the real world? If you’re providing your printer with press-ready PDFs (at Imlay, we like the PDF/X-1a’s), then it’s on you to make sure everything that bleeds has the proper bleed allowance (that is, you “pull the bleeds”). If you miss some, either your printer will spot the missing bleeds when they preflight or impose the files, or (worse) maybe you’ll catch them when you review the proofs. In either case you’ll need to pull the missing bleeds and supply replacement pages. All pretty straightforward, if a bit of extra work for you. (With control comes responsibility, Grasshopper.)
Things start to get a little tricky when you furnish native files to your printer. In that situation, someone like me is going to preflight your files and, among other things, try to spot and pull any missing bleeds. If a solid-color box is missing bleeds, that’s easy. But what if it’s a photo with no bleeds? Or a complex polygonal shape? Or a gradient? Or a group with an effect applied to the group? It can get pretty messy and result in schedule disruptions owing to the extra time it takes to rectify the issues, or even (but rarely at Imlay) additional charges.
The situation is further complicated by the fact that InDesign has a commonly used display mode (“Preview”) that hides the bleed area. When I open a client’s ID file and it’s in Preview mode, I’m not surprised if there are missing bleed allowances. A good way to avoid missing bleed allowances is to set bleed guides (in Document Setup… in InDesign or on the master pages in QuarkXpress), make sure any bleeds on the master pages go all the way to the bleed guides, and take a final, page-by-page run-through to look at bleeds before you send files to your service provider.
The concept of a safety area isn’t related to bleeds per se, but it’s about bad stuff potentially happening near the edge of the page, so I’m throwing it in here. The basic idea is that you don’t want live elements (type, head shots, etc.) to be too close to the trim, because you may find that the edges of these live elements get sliced off on some printed copies. Sometimes (for example, in magazine ad guidelines), the safety area will be specified, but in the absence of explicit guidance, I’d suggest that you keep live elements a minimum of 0.25 inch (1p6) from the trim, and 0.375 inch (2p3) would be even better. Again, if in doubt, ask your printer’s rep.
Fairly frequently, for reasons that somewhat elude me, designers like to put narrow graphic elements along the edge of a page. We unwashed prepress types call these bleed bars.
Bleed bars look great on a Web page (check out the very top of this page, for example), where there’s no need for a bleed allowance and the trim is always perfect. In print, however, a nice narrow bleed bar is like a big neon sign with a pulsating arrow that says, “Looky here! The trim is off by 1/32 of an inch!” Without that bleed bar, the reader would be unlikely to notice a slight inconsistency in the trim. Because of this phenomenon, I’d recommend that the width of a bleed bar should never be less than 0.125 inch (p9) and preferably at least 0.25 inch (1p6).
Curmudgeon that I am, I’m fairly certain the issues I’ve described here (and others that I’ll get to in subsequent posts) result from designers becoming increasingly disconnected from the analog, ink-on-paper side of things. Page-layout software has become so mature and has been around for so long, there’s a tendency to think that if something looks good on screen, then it’ll be fine in print. Try not to get sucked into that fallacy. Back when dinosaurs roamed the earth and I was starting out in print production, everyone was a lot more worried about how the physical product would turn out. That’s probably healthy.
I’m always interested in what you have to say, so don’t hesitate to leave a comment.