Opaque vs. Transparent Colour on Metal

Transparent ink allows the substrate to participate

A transparent ink allows more of the underlying metal to remain optically visible.

On exposed aluminium, the natural reflectivity of the substrate can become part of the colour appearance, producing greater metallic or reflective character.

Opaque ink reduces interaction with the metal

An opaque ink reduces the visual influence of the substrate beneath it and generally produces a more solid appearance.

The substrate is still part of the production system, but its optical influence is reduced.

The following should not be treated as equivalent production specifications:

The requested colour target is the same. The physical interaction with the substrate is not.

Basecoat changes the relationship again

An opaque white base creates a more neutral printing surface. Without a white basecoat, the metallic substrate remains more directly involved in the optical result.

Basecoat availability is factory, substrate and production-line specific.

Metallic appearance does not necessarily require metallic ink

Transparent or semi-transparent colour printed over exposed aluminium can use the natural reflectivity of the substrate to create metallic character.

This effect should be evaluated physically rather than approved through RGB simulation alone.

Related technical references

• Colour on metalWhy RGB Is Not Printed Colour→
• Production controlHow to Select a Colour for Can Production→
• Printing systemHow Beverage Can Printing Works→