Its a Trap!
Well, not really, its just another in a series of posts about printers terms and tools here at cutpasteandprint. Today we are covering the term Trap as it’s used among printers.
Trap, like bleed, is essentially a fail-safe, a way of preempting problems when dealing with all the various machines involved in printing. In a perfect world all printing presses would register perfectly all the time, and never waver from that perfection. But in reality, achieving excellent printed materials comes from the combined skills of talented pressman and a pre-press department with an eye for detail.
Trap, as it turns out is a way to give a press a little leeway in printing multiple colors. Lets take a look at an example.
In the logo above, we have a design with 2 colors. A large chartreuse field with magenta text laid on top. Imagine a press printing out this design. First it impresses the chartreuse ink, and then next impresses the magenta ink in place. Now imagine this same action happening 10,000 times. Somewhere during the process there may just be a little bit of bouncing, a wavering, or a wobble, or two. The green might shift a bit, or the magenta might lower just slightly.
Without a trap on your design, you might end up with something like this.
Notice the white space around the letters? Images seem a little bit out of alignment? That is what can happen without a trap. Perhaps you have seen little white gaps like this on the packaging of something you’ve purchased, or in the Sunday comics? Definitely not good for printed material.
So how does this happen?
Well, usually inks have what is called a knockout. This means that (in our example) any places you are printing magenta ink shouldn’t have any chartreuse ink underneath, instead it should just have plain white paper underneath. In our example, the magenta knockout would look like this:
The knockout prevents mixing and in this case prevents the letters from becoming orange-y instead of a pure, clean magenta. But this also means that if the press’s registration were to slip from perfect alignment, the white paper would be exposed and a little gap would show up in our finished product.
So how do we fix it?
One of the most common ways is to adjust by adding a trap. And a trap is basically just an overlapping of the inks, just slightly, to give the presses a little wiggle room. We usually use a type of trap called a spread. This is when a lighter color slightly overlaps a darker color. This lets the dark color define the edge of an object which keeps it crisp and clear. Take a look at this detail of the ‘T’ from our design, can you see the overlap?
This is our trap. Now if the press slips a little we have a space that won’t show the white paper, and we won’t notice any problems in the finished piece.
Once again, a little more time spent preparing files for press can resolve or eliminate headaches afterward. Of course you can set up your design to trap yourself – in fact a lot of software will handle this automatically for you. Of course if you have concerns about colors being too close, or tight registration, than by all means reach out to your printer and they can get your image set up to avoid problems.
The team at cutpasteandprint, would of course be more than happy to help.
