What is an underbase? What is it for? When will one be needed? These are a few questions that get asked a lot so we thought it would be best to explain underbasing in a nutshell in this handy article.


An underbase is essentially a layer of white ink covering the area of the design, printed before any other colours. This ensures that colours stay true and maintain opacity when printing colours on dark garments.


Screen Printing inks aren't very opaque, in a sense that they are quite thin. This is so colours can blend & mix when printed and so it can be printed through finer mesh screens for better detail hand softer 'hand' or 'feel'. In most cases when printing on dark coloured fabric with plastisol or standard waterbased inks, a white underbase layer first needs to be printed as an "undercoat" before printing the coloured inks. This ensures the print is vibrant on dark garments. It is somewhat like a primer when painting a wall in your house; the primer seals and smooths the surface and presents a good surface to paint onto. 

Here's a visual example:

With An Underbase.png
No Underbase.png

The animated image on the left displays the underbase screen printed with white ink, with the other 3 colours printed on top. The middle image displays the final print with an underbase. The image on the right displays the colours printed without an underbase screen, directly onto the black garment. See how much brighter the middle one is? This is all thanks to the mighty unsung hero of screen printing - the underbase.


Printing an underbase is necessary when the ink colour is lighter than than the garment colour. This applies to most garment colours with the exception of white & light / pastel colours. In some cases Heather Grey shirts also need an underbase, depending on what look you're trying to achieve. We'll be able to advise you on this during the quoting process. Take a look at the examples below for a better idea of printing onto heather garments. If your design is white ink only, we will only need to make one screen, meaning you will not have to pay extra screen setup fees.

White ink print on a heather t-shirt with no underbase. Notice how a hint of the heather texture shows through the print. This is sometimes desirable when going for a 'vintage' feel to your design, which is quite a popular request.

White ink print on a heather t-shirt with an underbase. Since the design is already white we would simply print twice to create a stronger image. If the design was another light colour an underbase may be needed if you don't want the heather texture to show through the print. 

That should bring you up to speed with underbasing but if you have further questions please get in touch below. We're always on hand to help! All clued up and ready to get a quote? CLICK HERE.

Underbase Flow Diagram BLACK.png

Use the flow diagram below to figure out wether you may need an underbase for printing your design.


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