The printing company will trim up your job after it has been printed, collected and put together so that it has a nice clean sharp edge. Which is why you had it professionally printed in the first place!
Why have a bleed?
The most obvious reason is because you want to print an image to the very edge of the paper. Professional printing machines - and most domestic ones for that matter, - can't print to the edges. Normally they leave a small gap, since you don't want ink all over the place inside the machine. Incidentally, even one-off inkjet prints in my opinion shouldn't be printed using the edge setting, if the printer supports it; because this can still result in ink everywhere.How can we set a bleed?
To enable this to happen when we are art working a publication for professional print - of any kind -then we incorporate in our artwork a bleed setting so that the printer knows where to trim. Even if you are not actually taking the print to the edges the printer will expect it and may reject your artwork if it isn't incorporated. definitely it is needed if you have images - or just colour that you want reaching the edges of the paper. For this short tutorial, I'm using InDesign as an example, although many other professional layout software works more or less the same. Word is not considered a pro bit of software for this purpose.Setting the bleed in InDesign
If you have a modern version of InDesign, then the file setup looks like the image below, the bleed setting is highlighted with the red circle. Note I've removed the side with all the presets on. Older versions look like the one below that. Bleed settings are usually 3mm for Litho or Digital print. If you are doing banners or posters, check with your supplier or use 5mm.
When you have done this, your document should have a red outline outside the page like shown here, the pink line is the margin - make sure you don't confuse the two:
All your artwork that you want printing to the edge should go over the edge to the bloodline. It's OK to take it further than this, you don't have to tidy up, as InDesign will just ignore it.
Practical example
So here's a job I just did and is at the printers right now. It's a flyer for some art exhibitions in about a month's time. This first picture is what the finished job wants to look like. The background image extends to the edges of the paper.
So to do this, I have set up the file with a bleed. In the next picture, you can just make that out under the background image, and you can see how the image meets the bleed:
Once the artwork has been completed, my suggestion, always print it out with trims so you can check all of this; you need to make a PDF to deliver to the printing company. They will in turn run a preflighting piece of software over your publication to check that it should print OK. Often, if you have forgotten bleeds it will fail this, so get it right. It will also fail for technically wrong colours of ink and pictures that are too low res.
Making the PDF
Making a good PDF from InDesign is straightforward. Go to File > Export then PDF (Print). Select your print setting from the top drop down. I usually use PDF X3 (2002) but ask the print firm. Many don't care that much now, but occasionally one will. Incidentally PDF X3 will give you slightly better colour if you are printing digital IF the process allows, although most times it makes no difference.
When you are in the PDF dialogue box make sure that you click on "Marks and Bleeds" and select "All printers marks" and "Use document bleeds". See below.
Now make your PDF by clicking "Export" InDesign will grind away for a short period and then your PDF will be ready. When you look at it it should look like this:
Congratulations!
What's on the print-ready PDF?
Your PDF incorporates a number of marks. Here's what they all mean and do:
- Two sets of trim marks the innerness where the printer will trim your print and the outer set are the bleed marks.
- On each side there are registration marks, used to align the separate colours when printing in full colour.
- On the top there are two sets of colour patches. You can use these to check the accuracy of any printing. If you print this out with the colour bars, you should get a nice even greyscaleon the left and colour patches on the right. If you do the on one of the college printers you notice that the dark end of the greyscale is hard to see any difference. One reason that these printers are less than satisfactory. Curiously, they print far better if you print from a PC rather than a Mac. Put your job on a memory stick and print out in the Library to see the difference! The reason for this is that the printers are calibrated for aPC colourspace and not that of a Mac/InDesign. I have tried to change this, but have failed. :-(
- At the bottom you can see a file name and the date and time of creation.
