What is Anodization?
Anodization is an electrochemical process that grows a hard oxide layer into the surface of aluminum and seals color inside it, so the finish cannot chip, peel or scratch off.
Anodizing grows a hard oxide layer into the aluminum surface and seals dye inside it. Because the color sits in the metal rather than on top of it, it cannot chip or peel. A second pass adds a further controlled layer over selected areas, which is how a cap can carry a brushed champagne body and a deep navy band without a printed edge between them.
The second pass is a manufacturing decision, not a decoration step — it has to be designed in.
Designers reach for double anodizing when a single-pass color reads flat under retail lighting, or when a two-tone effect has to survive a decade in a bathroom cabinet. It costs a second trip through the line, so the geometry and masking approach need to be settled before tooling is cut.
When to specify double anodizing
- Two-tone bodies where a printed or foiled division would show a seam.
- Deep, saturated colors — jewel tones especially — that a single pass renders thin.
- Programs where scratch and chemical resistance matter more than lowest unit cost.