Bleed, it’s an provocative word, but what does it mean in the world of print? In today’s article we’d like to crack this nut right open.
It’s an incredibly important concept, and relatively simple, but often misunderstood and mystified–some of you might be rolling your eyes right now (it is that simple, once you know) but from someone who works directly with the general public, no other fundamental print concept is so often a cause for anxiety. If you think you know the scoop and want to get straight to the point, you can jump to the main content.
But for now, let’s forget the all important bleed! I know I know, after all that? But there is a premiss that is required before the importance of bleed can become completely clear:
“Printers don’t print on regular size paper.”
“Regular” is probably a misnomer here, there’s no such thing. Printers do, however, in Australia and New Zealand, print using the International Standards system (ISO). This includes the paper sizes that most people are familiar with, A5, A4, A3 and so on, but also includes things like B2, C4 and oversized papers like SRA4. This last size, SRA4, is of particular interest to our little exercise. If you’re interested in seeing the full gamut of ISO paper sizes available, this paper size chart on the BJ Ball website is enlightening, though perhaps a little overwhelming to the newly initiated.
SRA stands for “supplementary raw format A”, which is 115% larger than it’s regular A format counterpart (there is also “raw format A” (RA) which is 105% larger, but not used as much). This size difference is the important linking factor to understanding the importance of bleed. An example of an SRA format sheet size against a regular A format sheet can be seen below.
So let’s say you have a single sided A4 flyer you’d like printed, lets call it our Bleed Flyer. You’ve set it up in your program of choice, you’ve exported it to a PDF, it looks great, you’re ready to print. In your file you’ve used a solid colour for the background, and that colour reaches all the way to the edge, like below, in our Bleed Flyer.
If we were to print this on regular A4 we’d end up with a white border (left in the example below) because we’d lose a bit of information on each edge where the printer couldn’t place toner.
On the right, in the below example, we can see the same file printed on SRA3. This is starting to look good, in this case we HAVEN’T lost any information on the edges because the printer had all the room it needed to lay down the toner… But there is still a big problem.
If you only wanted one Bleed Flyer, it’s reasonable to assume you could just cut that file out of the SRA4 sheet with a scalpel and call it a day, but lets say you need 1 million Bleed Flyers… then what? Well these flyers are finished by hand, by someone called a finisher–we’ll go what a finisher is in a later article.
The finisher uses a guillotine to cut large quantities of paper at a time, this is where bleed really becomes important. You can imagine that a machine that can print hundreds of flyers a minute can make some mistakes, these mistakes mean that the image on one sheet may not be in an identical place on the next sheet. Even if the finisher could cut the top sheet in exactly the right place, the likelihood is that the proceeding sheets would be inaccurately cut and would show at least one white edge.
So what is bleed? It’s literally the bleeding, of any image that you’d like printed to the edge, over the edge of the document’s final size/trim size.
If we want our image (or background colour etc) to go all the way to the edge, it has to overlap the edge by at least 2mm (I ask for 3mm standard, and 5mm for larger jobs or offset printing). Adding 3mm to each edge increases our A4 file size by 6mm vertically and 6mm horizontally, which leaves us with a file that is 216mm x 303mm (210 + 6 x 297 + 6) that has red all the way to the edge. Imagine you’re baking gingerbread cookies, and you want to use a cookie cutter to cut them out, the dough you use will be larger than the cutter so that the edges are clean. It’s very much the same concept.
So our Bleed Flyer, at 216mm x 303mm, has now got bleed and we’ve made sure that the red of the background passes all the way to the edge of the bleed. This is enough for your printer: if you explain how you’ve set the file up, that it has 3mm bleed, they’ll know what to do and where to make the cuts; but there is one more step which is industry standard and should be completed where possible.
As you can see in the example below, even with bleed, once the file is printed on SRA4, it’s not clear where the bleed ends and the file begins, it’s almost like we didn’t put bleed on the file at all (it’s there, all 3mm of it, you’ll just have to trust me). So the final step is adding printer’s marks, but in this case, specifically bleed marks.
Bleed marks help your printer understand exactly where the bleed ends and outlines the final size or what is known as the “trim size”. This is the final size of the document once it has been cut down. This minimises confusion, saves time, and ensures you get what you paid for–technically a file isn’t print ready until it has its bleed and marks.
Adding bleed is something that is done right at the outset of file creation, but the marks aren’t added until the time that the file is exported for print. In Adobe Indesign, when you set up your file, in the opening dialog box you are asked if you’d like to add bleed. Then when you go to export you are asked if you’d like to include bleed. This is an important distinction because if you haven’t added bleed to the document, there isn’t any bleed to export.
Obviously we can’t give an inclusive how-to on every program and way of creating bleed, there are endless resources on the internet however, but we can share with you what you’re looking for:
It’s important to note how the marks don’t meet, if they do they tend not to be cut off when the document is trimmed to size.
This simple understanding of paper sizes and the use of extra space and marks, should help you get the most from your next print job.