Glossary · Technology

UV printing

White underbase

A layer of white ink that is printed first and on which the colours then lie. It makes colours stand out on dark or transparent substrates.

Explained in more detail

UV inks are translucent, so they let the substrate show through. On white they look as intended, but on black, wood or metal they almost disappear. The white underbase is generated as its own channel in the software, usually automatically from the design, and can be offset slightly inwards so that no white edges show at the border. Opacity and number of layers control how strong the colours become. If the underbase is left out deliberately, the material shows through, which can be intended for wood or brushed metal.

Where does the term come from?

The term describes that white is printed beneath the colour. In English this is called “white underbase” or “white underlay”, and the principle has long been known from screen printing on dark textiles.

In practice

• Make the white channel slightly smaller than the design (choke), usually a few tenths of a millimetre, and eufyMake recommends 0.5 mm at most.
• For fine lines and small text, set the choke to 0 or make the elements thicker, otherwise no white is left underneath.
• On very dark material, increase the white density or number of layers; a test strip with several steps shows the best value.
• Too much white makes the layer thicker and the edge tangible, and it can crack more easily when bent.
• Print enough white under faces on wood or metal, otherwise skin tones quickly look pale or colour-cast.

Not to be confused

Not to be confused with reverse glass printing: there the white sits behind the colour as a cover, not underneath it as a base coat.

Frequently asked questions

Why does my UV print have a white edge?

The white is as large as the design or larger, and with a minimal offset it shows through. Make the white mask a few tenths of a millimetre smaller.

Do I need a white underbase on wood?

If the colours need to be exact, yes. Without white they become warmer and darker and the grain shows through, which is often intended with natural-coloured wood.