January 11th, 2017
Follow these tips to keep your white-on-dark print jobs looking sharp.
Mastering white-on-dark screen printing is crucial for your business: You inevitably will have customers who ask for white-on-dark prints, and you want to be able to meet their requests with quality products. To that end, we have some do’s and don’ts to help you create sharp and bright white prints on dark materials.
The Do’s of White-On-Dark Screen Printing
As with nearly all of screen printing, turning out a quality white-on-dark print depends on proper pre-press set up, along with employing proper technique. When setting up and carrying out your white-on-dark print, keep in mind that your goal to create a bright print hinges on putting down a healthy application of ink without compromising the quality or crispness of the print.
Here’s what you should be doing when screen printing white ink on a black or dark-colored product:
- Start with a lower mesh count screen. White inks tend to be thicker, and you want to make sure enough of the ink deposits onto your substrate. For white-on-dark printing, a 110-count screen is a good rule of thumb. For a more detailed design, you can go as high as a 156-count screen, or for a heavy application, such as block letters on a jersey, you can go as low as a 60- or 86-count mesh.
- Create a thicker stencil. Creating a thicker stencil also helps to deliver more ink to the substrate by creating a deeper well for the ink when printing. For white-on-dark printing, coat your screen on both sides with emulsion and let it dry. Follow with two more coats of emulsion, with dry time in between coats, on the outside of the screen. Remember that the thicker emulsion will mean longer exposure time.
- Set a larger off-contact. With a thicker ink deposit, you’ll also require a slightly higher off-contact distance to allow the screen to snap back cleanly from the substrate, leaving a crisp print behind. Off-contact for a white-on-dark print should be 1/16 to 1/8 of an inch.
- Print an underbase, flash cure, then print again. One of the most effective ways to get a bold print when using white or light inks on black or dark substrates is to print a white underbase. The proper way to do that is to print one layer of white ink, flash cure the print for 5 to 10 seconds, then print your top coat of ink. Just make sure that your underbase cools before you print on top. Otherwise the top coat of ink will stick, resulting in a rough handfeel.
- Be sure to thoroughly cure your ink. Remember that your white-on-dark print might have a longer cure time, because of the thicker ink deposit and because white ink will reflect the heat of your dryer. Use temperature strips or a temperature gun to make sure the entire deposit of ink is coming to the cure temperature recommended by the ink manufacturer.
The Don’ts of White-On-Dark Screen Printing
While following the above steps when printing white ink on black or dark materials should set you up for a bright, crisp print, there are a few don’ts to keep in mind. When printing white-on-dark, don’t:
- Thin your ink. Because white plastisol ink tends to be thicker than other colors, it can be tempting to thin the ink. However, this is counterproductive: It is difficult to get an adequate amount of thinned ink to create an opaque white print.
- Overwork your ink. If you are manually printing white on dark, you also might be tempted to do several passes of your squeegee over the stencil to lay down ample ink. Overworking your ink can upset the fibers in your substrate, causing fibrillation, or visible shirt fibers within your ink.
- Use your underbase as a final color. If you are printing a multi-color design that includes white, resist the urge to use the white underbase as a final color in your print. To make sure that the white in your design is as vibrant as the other colors, print a separate layer of white ink.
While white-on-dark printing intimidates many screen printers, by following the do’s and don’ts of proper setup and printing, you can produce crisp, quality prints that satisfy your customers’ requests. And like with any printing technique, having the right equipment goes a long way towards ensuring quality results. Let’s discuss the right tools for the job!