White underprint (white base)

A white underprint is an opaque white ink layer printed behind the coloured areas on clear or metallised film. Without it, translucent inks look weak and the product shows through the graphics.

How it is applied

In reverse printing, the colours are printed first on the inside of the outer film and the white goes last, behind them, before lamination. In surface printing the white goes down first. White is a full press station with its own plate or cylinder.

Full or selective white

Full white makes the pack opaque. Selective white leaves some areas clear, creating a product window, or lets parts of the design shine on metallised film while others look solid.

Watch-outs

A single white pass may not be fully opaque; a double hit or a white inner film such as white PE can help. Plan trapping so no thin clear lines appear at colour edges.

Tip

Set white up as its own spot colour layer in the artwork file and mark exactly where it should and should not print.