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What the Heck is an Underbase Anyway?

Apr 13, 2018

Underbase, underlay, overprint, print flash print–what does it all mean?!

You may have heard a multitude of nomenclatures for this process, but don’t let the laundry list scare you. An underbase by any other name would still be as necessary. It’s a pretty simple concept to understand, once you know a bit about the process.

Brush up on the Basics

If you’re totally new to this or still a bit fuzzy on how the whole screen print process works, we recommend you go over to our Basics of Screen Printing blog post and soak up that info before going forward. We’re not going to get too in depth here, but you’ll still need to understand some general screen printing concepts to wrap your head around the topic of underbases.

Alright, did you make it through to the end? Good. We know it’s a lot of info. Okay, so now onto what an underbase is, why it is necessary, and when it is used.

The Fine Details

If you’ve ever painted a room before, you probably understand how you often need more than one coat of paint to properly attain complete opacity. Say you want to paint a red room white. The first coat would leave the room looking pink. Only after the 2nd (and sometimes 3rd) coat would you achieve an opaque white. That same concept applies to inks in screen printing. If we printed a red shirt with one pass of white ink, the print would take on some of the shirt color, thus resulting in a print with a pinkish hue. This is where the underbase comes in.

An underbase is essentially just a primer coat for the subsequent inks to sit on. We print the underbase first and then the colors of the design on top. Bear in mind, an underbase is only necessary when printing plastisol on dark garments.

If that still doesn’t make sense, here’s a visual example:

The image on the left is just the underbase. The image on the right is just the final color, printed directly on the shirt without an underbase. Because it doesn’t have an underbase, it’s a bit dull, or, as we like to call it, a “Vintage Plastisol” print. The image in the middle is both the left and right prints combined. We print the white ink and then the color directly on top of it. Although it’s most common to print the middle option, the style of printing shown on the right is a great way to get a different look. You can even combine distress patterns with this technique to get some more mileage out of the vintage look. For more info on the various ink types and printing techniques we offer, head on over to our Ink Options page.

But Why Does an Underbase Cost More?

Still wondering why an underbase counts as an additional color? That’s because to print an underbase, we have to print a separate film, burn a separate screen, and print a separate color than what is shown on the final shirt. Hence why a white print on a black shirt is priced as a 2 color. The first color is the white underbase, then, to make the print completely opaque, a second screen is loaded with white ink and printed.

Just Give me the Bullet Points

That’s really all there is to it! It’s pretty simple once you have a few basic concepts under your belt. You just need to remember the following points when it comes to using an underbase:

1. It’s only necessary when printing with plastisol inks
2. It’s only required when the final ink color is lighter than the shirt color
3. It’s a primer for subsequent colors
4. It counts as an additional color

Hopefully you feel like an underbase expert now! Head this way to get a quote!