High density screen printing can make any logoed or artistic print standout. Available in plastisol, gel and even water-based varieties, high density inks are laid down in a thick layer, and they cure with crisp, sharp edges to create an eye-catching 3D print.
High density inks generally come in black and white, while the gel is clear, and you can mix them to create the color print you want. High density inks will cure with a matte finish, while gels will cure to a high gloss, giving you the flexibility to create the exact look you want. Some high-density inks come flecked with glitter, and they are a popular option for overlaying with foils to create a 3D metallic print.
Screen printing with high density inks and gels does take some special skill. Because they require higher curing temperatures, high density printing can only be done on cotton or cotton-blend garments, and printing on white garments can be difficult to achieve without scorching the garment during printing. To achieve the raised, crisp final effect that’s desired with high density screen printing, you have to lay down a thick, clear layer of ink and that thick layer of ink needs to be cured completely. While you will have to be prepared to practice screen printing with high density inks, here are five things you need to know to get started:
High density inks and gels have high viscosities, which makes it harder to get the ink to flow through the screen. On top of that, you want to lay down a thick deposit of ink to achieve a raised, 3D effect on your final print. To accomplish this, you have to use low mesh count screens with thinner threads when undertaking a high density printing job. Use a screen with a mesh count between 80 and 83 and a 70- to 71-micron thread.
That heavy deposit of ink also requires a thick stencil. Because it would take so many layers of emulsion to create a thick enough stencil for high density printing, most experienced high density screen printers recommend using a capillary film that is between 200 and 400 microns thick. Rather than applying the film with water as you normally would, place the film on your screen and secure it into place with a layer of emulsion. To further secure the film and create a heavier stencil, apply two more coats of emulsion to the inside of the screen using a scoop coater. Keep in mind that with such a thick emulsion, you will need to let your emulsion dry for several hours, or even overnight, before exposing it and washing it out.
When you print with high density inks, your print is going to sit higher off your substrate than typical prints. To give the ink ample room, and to give the screen enough room to snap clearly off the ink during printing, you need a higher off contact on your press. Your off contact for high density printing should be about double what it normally would be when printing with normal plastisol inks on your chosen substrate.
To maintain a crisp edge and avoid squishing the ink through the stencil during printing, high density printing requires soft pressure. Try a 55/90/55 triple-durometer squeegee with a low angle when high density printing on a manual or automatic press. Flood the screen first to fill the stencil with ink, then use a gentle stroke to lay the ink down onto the substrate.
High density prints are, well, high density. That means that it takes a lot of heat for a longer period of time to cure the ink from the surface to the substrate; to apply enough heat, you likely will have to increase the temperature and slow the belt speed on your conveyor dryer. Most high density products cure between 325 and 380 degree Fahrenheit (as always, check with your ink manufacturer for curing recommendations). While using a thermometer or probe to test the temperature of the ink is only way to be sure that the print has cured through, the look of the print should give you an idea of whether the product has fully cured. High density plastisol inks should be matte with sharp edges when cured; a glossy appearance indicates that the ink has not set. Cured high density gels are glossy with rounded edges; uncured gel will have the matte appearance and crisp edges of a high density plastisol print.
Printing with high density inks takes, perhaps, a little more experience than printing with other types of special effects inks. In the end, high density screen printing can help you achieve stunning prints with interesting texture. The “wow” factor of high density ink can add a crisp, professional look to logos, and it can make for a more intricate and eye-catching fashion or artistic screen-printed image. With some practice, you can master high density screen printing.
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