Marshall Atkinson guides you through the nine circles of print registration hell
The Inferno is the first part of Dante Alighieri’s famous story, the Divine Comedy, which you may well have been forced to read in school and no doubt have since long forgotten. In the tale, Dante is journeying through hell, with the poet Virgil as his guide through the nine circles of suffering.
That’s not unlike what it feels like to have registration problems on press with a deadline looming. Before you crank down on the squeegee pressure to solve your problem like a rookie, or worse, storm up to the art room like a maniac, settle down and check out these nine common problems to see if they show up in your shop.
1. Who is minding the store?
The keystone to screen printing T-shirts has always been the quality of the screens. For some shops, the problem employees always seem to wind up in the screen room: the screen room shouldn’t be a purgatory level for your staff. There are a lot of steps to making screens properly. Are your employees following them perfectly? How do you know? How much time do you really spend in there?
Every screen should be meticulously created and exact in its purpose. It doesn’t do anyone any good to have a perfectly coated screen that has been imaged and exposed properly, and during the wash-out phase the worker blows out all the halftones with a pressure washer. Slow down and do it right.
Your screen room should operate like a store with your screen printing department as its only customer. The screen room staff should do anything and everything they can to make their only customer happy. Make sure they are up to the challenge.
2. Screens: What to look for
For screen tension, most industry experts agree that you need around 20 newtons for an acceptable image for T-shirt printing. For super high-end work with a lot of halftones and detail, you want to be in the 30+ newton range.
The higher the tension the better, as this also affects your ink deposit and how you shear the ink with the squeegee. What happens with low tension screens is that as the squeegee travels the distance across the screen, the screen flexes downwards towards the shirt, like a trampoline with a kid jumping up and down. If you have ever had a problem registering your underbase plate with the image peaking out underneath above and below the art, this could be due to a screen tension problem.
3. What about the art?
Occasionally the art will be the culprit for the registration challenge. First, the file could be improperly separated. That’s an easy check: just pull it up on the computer and compare it to the currently printed version to see what’s off.
Next, it could be the separation plates. You’ll have less trouble if the files are sent to the screen digitally. If you are still using vellum or film, your problem could be with the substrate you are printing your image with. Vellum can be affected by humidity, and slight changes can occur. For film, I’ve seen issues with plates where half the screens were printed with the end of one roll, and the rest at the beginning of another. For some reason, these don’t line up that well. Sometimes it pays to do jobs with lots of screens with a new roll of film.
4. Locked and loaded
For some shops that have a big enough wallet to have a direct-to-screen system for imaging the screens, the problem could be that the screen wasn’t nestled into the device correctly. Regardless of the manufacturer, screens need to fit tightly against the machine frames and be locked in.
For shops that are still taping their plates onto the screens, a similar problem could be occurring. Either the screen isn’t being nestled into the table jig you’ve set up, or the plate shifted when you were taping it to the screen.
Remember, consistency is important. If you are judging your screen room by their output, they may be taking some shortcuts to increase their quantity of screens per shift.
5. On the level
On press, if you have registration issues that only occur once every few shirts, you could have a challenge with your boards not being level to the screen. What you will see is a slight shift in the print, usually left or right, on the image. If you print a lot of shirts, you should be checking this at least weekly.
A simple way to check to see if your boards are level is to use your on-press flash unit as the standard to measure by. Rotate the boards around and note the distance between the bottom of the flash unit and each board with a ruler. Everything should be the same. If you find one or two that are out of standard, adjust them.
6. Operator error
If your staff member is still eye-balling the screens for registration and not using Tri-Loc or another registration device, you might want to consider getting them some help setting up.
I’ve seen a lot of debate over the years on where to put the registration targets on the job, and what they should look like. In my opinion, for T-shirt printing, you just need a set centred on the screen with one above and one below the image. Some shops go the four-corner route, but to me that is just more stuff to tape off later.
If you are using registration targets that are centred with the image, you can line them up with your platen by having a simple line drawn down the middle of the board. This gets the image lined up with the machine quickly. Top. Bottom. Done.
For registering on press, use the underbase screen or the black screen to start; whatever screen all of the other colours will have to be adjusted to is what you want. Get that screen set up first and print an image on a junk shirt or pellon. Flash cure it, then register your next screen with that.
If you can’t get the screens to register, only change one thing at a time. If you change multiple things at once you can’t be sure what worked or not. If you want perfection, use a loupe and your micros on the press to really dial it in.
7. A sticky situation
Another common registration issue is the use of adhesive on the platens…or lack thereof. As the shirt goes around the press, it gets picked up from the board because it wasn’t tacked down enough.
Keep a can of spray tack handy, or a cheap condiment bottle filled with glue that you can quickly card onto the board.
For fleece and hoodies, a good trick is to have a roller or lint screen positioned before the first ink screen. This not only smooths out the fabric, but flattens it down into the adhesive on the board better.
8. Flex your muscles
What’s the number one answer for lazy printers to combat registration issues? More squeegee pressure of course! It’s the answer to everything evidently (note: sarcasm alert!). Gorilla-armed printers aren’t using their head to resolve the real issue: remember, if you can see your printed image on your press boards after you’ve removed the shirt, you are using too much pressure. The ink should sit on top of the shirt fabric, not be driven through it like a nail.
9. The invisible problem
When there are registration problems and nobody says anything, it is the entire crew’s fault. Each shirt should be perfect. When the customer opens the box, angels should sing. Make this happen by having a great team and constantly train and set them up for success. Have the work order and art mock-up on the table so they can review the order. After the first strike off, position it as the sample for the order (even if you aren’t keeping one for reference later) so that they can see what a perfect shirt is supposed to look like.
You want to find your mistakes and have an opportunity to correct them, because the worst problem of all – and the reason it’s the ninth circle of print registration hell – is when your customer finds your mistake. Either they call up your company and start the process of getting a credit or the order reprinted…or worse, they just never come back.
Stay out of hell
So, how do you avoid hell? By doing the right things, all the time, even when nobody is even looking. As printers, we have to be dialled in perfectly to achieve superior results.
One last word though. All the gadgets and industry tips go out the window if your production leadership isn’t on top of these problems. It’s your job to stay out of hell.
Marshall Atkinson is the owner of Atkinson Consulting, LLC, a service firm focused on the decorated apparel industry for process improvement and efficiency, sustainability, employee training, social media marketing, and long term strategic planning. He has over 20 years experience in the decorated apparel industry and has championed two companies to become SGP certified sustainable printers. A frequent trade show and webinar speaker, he also publishes his own weekly blog.