When is printing with opaque white recommended?

Opaque white is used as the fifth printing ink on silver film or transparent film. Excellent effects can be achieved with silver, similar to what you’ll be familiar with from hot foil stamping. Only, here, the procedure is reversed. We start with silver film, partially print it with opaque white, then with 4c. So any shade can also be given a metallic look on the label.
The situation is similar with transparent film. Underlaying with white is advisable to create opaque colours. If the labels are to be applied to a dark background, fonts and graphic elements can be white too.