White underprint labels – what's so special and how do I create the layout file?

behind-glass label sample
Sample of a label that is applied behind glass, produced with white underprint layer

On transparent labels with white underprint, the design is well visible, independent from the background that is provided by the surface the label is applied to. Normally, the printed CMYK colors on a transparent label are not opaque enough and the underlaying surface shines through the sticker. With a white layer underneath the colors (printed first or last, depending on whether the sticker is applied behind glass and therefore mirrored or not) the underprinted areas become more opaque.

Behind-Glass labels – applied indoors, visible outdoors

These type of label is applied on windows or glass doors from inside, showing it's actual print to the outside (through the transparent glass). Usage scenarios for such labels are store windows, car windows etc. In addition, the sticker is protected by the glass against weather influences.

Behind-glass labels are produced with an additional white layer at the end of production line, therefore it is a white overprint. Without it, all colors would be less opaque and shine-through, especially light colours or shades of black colour channel.

Here is how to prepare printing data for white layer: ( e.g. with Adobe Illustrator )

Please create an additional layer called "white layer" in your file. Fill all areas, where the white layer should apply, with 100% black and define the color as new spot color, called "white" (although the visible color is black).

Advice: To avoid "flashes" (where the white area flashes over the actual print) keep the shape of the white layer 0.5-1.0pt smaller than the elements that are printed in CMYK. Due to technical tolerances, there is a minimum offset when it comes to print of the additional color. Sample:

back to all guides