How to increase screen open time with PERMAPRINT Premium Inks for paper and other substrates
PERMAPRINT Premium Inks are highly pigmented water-based screen printing inks with a high resin/binder content so there is very little free water. Evaporation of water from the ink (air drying) is all that is required to cure PERMAPRINT Premium prints – while that’s great for the environment - and great for paper - you WILL need to minimize this evaporation while the ink is on the screen.
During printing there will be some loss of water with a tendency for the screen to seize up if the water-based ink is not handled correctly. The following tips will help you get around this:
- Use monofilament polyester screen mesh.
If you’re used to using multifilament mesh, consider changing to monofilament; multifilament mesh are more prone to drying-in. To achieve best results use 86-305 tpi for PERMAPRINT Premium Metallic Pearl colors and 86-225 tpi for Opaque White and Matting Agent.
- Clean and dehaze your screen.
Make sure that the screen is completely clean and dehazed particularly around the edges before re-coating the screen with water resistant emulsion.
- Ensure that the water resistant emulsion is totally dry before exposure.
If you rush and expose early the emulsion will break down and can become tacky during the print run.
- Also ensure that the emulsion is completely cured during exposure.
With a water-based ink, particular on long runs, failure to cure the emulsion will lead to shredding of the image.
- Set up your work area before you start printing.
Have your work area ready to go with everything you need on hand and be prepared to work quickly.
- Have a spray/spritzer bottle handy.
As part of the set-up, have a spray/spritzer bottle on hand filled with either straight water or water with anywhere between 10-50% PERMASET Print Retarder.
- Soak the screen in water for 5 minutes.
Just before starting the print run, let the screen soak in water for 5 minutes. Allow to drain and dab off excess water with a damp, lint free sponge. This will prevent water from the ink being absorbed into a dry mesh, drying out the ink and will improve ink release.
- Add a tiny amount of water to the PERMAPRINT Premium ink if needed.
You can also add some drops of water (1-2%) to the ink if it’s already too stiff. Generally, the ink is supplied at or slightly below ideal print viscosity and thickens up over time on the screen.
- Add just enough ink to get a good flood.
It’s better to start with just enough ink to ensure a good flood and add fresh ink periodically during the print run.
- When printing ALWAYS leave the image area flooded between prints.
The print sequence should be FLOOD, PRINT, crack the screen off the paper, then FLOOD prior to taking the paper off the table. Failure to flood between prints will exacerbate drying-in problems.
- Spray with spritzer bottle if the flooded area looks a bit dull.
If the flooded area starts to looks a bit dull, then spray lightly over the ink area with the spritzer bottle until the ink looks glossy again.
- Maintain workroom humidity levels between 40-50%
Some print shops position humidifiers near their print areas to maintain optimum humidity levels for longer screen open times. Others use reptile foggers for directional humidity control.
- Wash up as soon as you finish printing.
Recover unused ink from the screen and store in a clean sterile labelled container. Prolong the life of the screen by immediately washing with water and follow sustainability principles for disposal of runoff water.
Mindful screen printing practices with PERMAPRINT Premium water-based inks for paper and other substrates will yield not only bright, archival quality prints but will also contribute to a sustainable future.
 This will be covered in a separate blog post.
Patricia Del Favero is an independent designer and consultant that specializes in design and education. The information provided here is based on her experience and interaction with users of PERMASET eco-friendly inks. For the purposes of full disclosure, Patricia occasionally consults for Colormaker Industries, manufacturer of PERMASET Inks.