A screen printing job takes a lot of man hours. The whole process, from art prep to screen reclaim, takes time and effort to constantly hone in processes and learn from mistakes. The pre-press process — everything you do before setting up the press for a print run — is a big part of the screen printing process. Want to improve productivity and streamline this process? Here are six ways to dial in the pre-press process.
The darkroom is important to get the best screen for a job. You can have the best products, but if the darkroom isn’t dialed in it will be all for nothing. First, you’ll need to block out all light. This means UV light from windows and door frames and switching out UV bulbs to safe lights, like yellow or red bulbs.
Keep the darkroom at low humidity: below 40% is best. The space should be around 75°F. A hygrometer and dehumidifier will help control and monitor the humidity and temperature. Get a drying rack or build one yourself to store screens. Set up fans to blow across the screens to dry them faster.
Once the climate is right, let’s focus on the washout area. You’ll need a good place to degrease, rinse, and reclaim screens. Get equipment that works for your shop. You’ll need a washout booth or utility sink and a filtration system. There are many different sizes of washout booths, so you can find one that fits in your shop space. A filtration system keeps gunk from getting into your pipes. Invest in one, or create your own.
The last thing you’ll need to complete the darkroom setup are cleaning chemicals, a power washer, and dedicated scrub brushes for each chemical. By dialing in the darkroom, you’ll be able to lay the framework for creating great screens before you even touch them.
All screen print jobs start with art. Whichever method you choose to create art, always keep improving on it. Make mistakes, experiment with shortcuts and hotkeys, and make your design program work for you.
There’s also tons of courses you can take to hone your art skills. Learning Adobe® Illustrator? Check out this free course that walks through the basics of art preparation for screen printing. Dabbling in Procreate? There’s a free course for that, too.
No matter which software you choose, do some research and find what works for you. Keep learning and always strive for improvement.
Once the art is created, it’s time to print it. There’s lots of different film printer options. Find the best one that works for your shop at your price point. Photo printers are best because they’re designed to reduce UV light. On many printers, you can adjust the settings for best ink density and UV stoppage.
A tool advanced printers use is RIP software. If you have a detailed design with shading or realistic looking effects, then you will probably have to use halftones to achieve the look you want. Halftones will help to enhance your design’s detail and depth. But halftones also require that you make a few digital adjustments to your design before taking it to the press. That process, a “RIP,” is accomplished with Raster Image Processing (RIP) software.
Art is ready to be printed and settings are dialed. Grab a waterproof film, load it into the tray, and hit “Print.” Watch the magic happen, and you’re ready to head into that dialed-in darkroom.
There’s tons of different types of screens: high mesh, low mesh, yellow mesh, white mesh, thin thread mesh, and more. Which one is best to use?
Here’s a question to ask yourself: is the ink type more important in the print, or is the design resolution more important? If the answer is ink type, follow mesh guidelines for the specific ink you’re wanting to use. For thinner inks like water-based inks, go for a higher mesh count, like 230 mesh.
If you answered “detail resolution,” then choose mesh count according to the detail in the design. Higher detailed designs use higher mesh counts. The most versatile mesh count is 156. It can resolve high detail, but still lays down a substantial amount of ink. The best way to find the best mesh for a job is to test, experiment, and make mistakes.
So you’ve chosen your screen. Take it to the washout booth and degrease it if the screen hasn’t been degreased during your last reclaim. Even brand new screens need to be degreased. Once the screen is clean and dry, it’s time to coat it.
A 1x1 coating method is the most common. The first number in this equation represents the T-shirt side of the screen, while the second number indicates the squeegee side of the screen. The more coats of emulsion a screen receives, the thicker the stencil will be, and the more ink you’ll lay down on the garment. For a thicker stencil, use a 2x1 or 1x2 coating method.
Pro Tip: Always finish coating a screen on the squeegee side. This way, the emulsion will transfer through the screen, giving you a better stencil. Dry screens T-shirt side down to enhance this gasket on the squeegee side.
Coating screens can be done on the floor, by propping the screen up and leveraging it on the floor. A coating stand is a great way to take coating screens to a whole new level. You won’t have to kneel on the ground to coat screens. Simply create one out of scrap wood, place the screen in the stand, and coat like a pro.
Which emulsion works best for your shop? There’s a few factors that can affect this decision. Here’s a breakdown:
Whichever emulsion you choose, make sure to read the product description. It gives coating tips, exposure time recommendations, and has other helpful information you’ll need to know.
Once a screen is coated, set it in your drying rack T-shirt side down to dry. Treat yourself to a cup of coffee while you wait, or get started on another part of the job. When the screens are dry, it’s time to expose them.
Take the dried and coated screen out of the drying rack and align the film to it. You can do this with a T-square or a registration template. Once the film is aligned and taped down, it’s time to expose.
Get the best exposure unit for your shop and your budget. Exposure units vary in size, features, and price. There’s two main types of exposure units: vacuum units and compression units. A vacuum unit creates a tight seal around the screen and film, creating excellent positive contact that can expose crazy detail.
Compression units can still expose detail, but the printer has to create positive contact themselves. Take the Baselayr X1620, for example. This unit doesn’t have a lid, so you’ll need to create the compression. Check out this blog to learn how to do it.
LED light is the new standard for exposure. LED exposure units can expose more detail, create more stencil durability, and create overall better exposures by crosslinking the emulsion more thoroughly.
Depending on your shop and budget preferences, get the best exposure unit for your budget and upgrade when it’s time. It’s good practice to future-proof your purchases. Buy a piece of equipment that you can grow into. The vacuum exposure unit is a big upgrade, and may be risky to purchase. However, you’ll be able to grow into it instead of outgrowing it the moment it arrives in your shop.
Now that your darkroom equipment is dialed in and screens have been exposed, it’s almost time to start printing. Before you head directly to the press, though, you’ll need to choose some printing supplies. Let’s look at a couple of them.
Ink is vital to screen printing, so make sure to choose the best ink for the job and your shop conditions. Got a shop in a dry area, where it’s hard to control the humidity and temp? Go for plastisol ink. Looking for a thin ink with a super soft hand feel? Choose water-based ink.
Whichever ink you choose, make sure it’s best for your shop setup. Test it out before you buy a whole shelf full of ink to make sure it has the capabilities you’re looking for.
Now, let’s talk squeegees on a manual press. Wood handled squeegees are the most common type of squeegees, as they’re the most economical type. There’s a couple other types of squeegees out there. The Ergo Force squeegee is made from aluminum and is comfortable to hold. Then, there’s the EZ Grip squeegee. This squeegee is perfect for taking on long jobs. Its upright handles make pushing or pulling easier than ever. Whichever squeegee you choose, make sure it’s about an inch larger than the design on either side.
Now, let’s talk squeegee durometer. The durometer of a squeegee is how stiff the squeegee blade is. A 60 durometer squeegee will bend a lot more than an 80 durometer squeegee will. The more a squeegee bends, the thicker ink deposit it will lay down on the screen. For jobs with lots of fine detail or thinner inks like water-based ink, a harder squeegee durometer comes in handy.
Most printers opt for a 70 durometer squeegee as it’s more versatile. If you’re printing with plastisol and need higher detail resolution, go for a 70/90/70 or 80 durometer squeegee. Printing high detail with water-based ink? You’ll want a 65/90/65 to 70 durometer squeegee.
There’s so much that goes into getting a screen ready for production on press. That means there’s also so many different methods to speed up this process. The best advice? Do your homework, test, and find what works for you. Document as much as you can so you know what worked and what didn’t.
Find the best internal process and products that suit your shop within your budget. Dial them in and get the most out of them. Do you like to coat a bunch of screens at one time, so you have them ready when you need them? Do that. Like working through the darkroom in a clockwise direction? Set it up!
Beyond processes, there’s a ton of supply upgrades that will improve production speed and quality of the final product. Take the registration template, for example. It’s a transparent sheet that shows where the platen is in relation to a screen. The template has pre-marked registration lines so all you need to do is line everything up and tape the film down.
Another great upgrade is aluminum screens. Aluminum screens won’t warp as much over time, so you’ll have better screens for longer. When you’re ready, start upgrading your darkroom setup too. Invest in a vacuum exposure unit, buy a bigger washout booth or a filtration system, even build your own drying cabinet. There’s so much to upgrade, you’ll find yourself looking back wondering “how did I do it?”
The pre-press process can be a long one, especially for those learning how to do it. Don’t worry about messing up: it’s part of the process. Every printer started somewhere and learned by making mistakes. Dial in your process and you’ll soon be crushing it just like the pros.