HPI white: why and when?

What is HPI white?

In this blog we explain why and when to use HPI white. Below we tell you how to order and format opaque white in your print file and you can download sample files. Opaque white, also called HPI white, is white ink. It is applied to label materials that are not white for a number of reasons. These include the materials: transparent PP materials, metallic materials (paper or PP) and those that are somewhat darker in color by themselves, such as grass paper.

But why and when is opaque white needed?

To explain that, it is helpful to start with the printing technology. You should know that our digital printing machines ‘print’ inks that require a white background to appear opaque and clear. This is because the ink itself is not ‘full-face’ opaque. Fortunately, most of our materials, such as glossy white paper, natural paper or PP film, are white in color. If we print the same colors on transparent film, for example, we can see what effect the lack of a white background has: the print is not opaque and is therefore a lot less bright. By the way, the reason why called HPI white can be used to make colors look bright on non-white materials is that this special printing ink is completely opaque. (This also applies to the “color” black, by the way).

Use HPI white with transparent materials

On transparent materials, HPI white is used to make color printing opaque so that the colors come out brightly. We then print wherever color is required, first the cover white and then the relevant colors.

Use opaque white with silver materials

Silver materials (silver PP or paper) lend themselves perfectly to stunning visual effects. Printing a color directly on the silver layer creates a metallic shimmer: for example, gold, copper, or metallic red. Usually, the entire label is not intended to have a metallic appearance. And then it’s time for opaque white: the elements you want in a normal color or white on the label are printed with opaque white. Any other colors you want, we print on top of that layer.

HPI white on dark paper

Even on darker paper, think grass paper or kraft paper, we often use opaque white.The fact is, digital ink is not opaque and so the colors would look much darker because of the dark background. HPI white as the first printing layer under color printing ensures that the colors will be as fresh as they are meant to be. If you intend to have white printing on these labels, there is no need for a second coat of HPI white.

How do I order HPI white and prepare the files?

Placing the order: if you need opaque white on your labels you must indicate so in the ordering process (the option appears automatically when transparent, silver material or grass paper is chosen in our on-line calculator). For kraft paper: please contact our customer service. Layout of print files: opaque white must be included in the print file in a special way, see our guidelines.