Titanium colours explained: anodising and voltage

Gold, purple, blue, pink, teal and green titanium can look as though it has a coloured coating. Traditional decorative titanium anodising works differently: the colour comes from an extremely thin, transparent oxide layer on the metal.

How does titanium get its colour?

Titanium naturally forms a thin layer of titanium oxide. Anodising thickens this oxide layer through a controlled electrochemical process. Light reflects partly from the top of the oxide layer and partly from the metal underneath. These light waves interact, a phenomenon called thin-film interference.

The oxide-layer thickness determines the colour you see. No dye is added to the titanium during this process.

What does voltage have to do with colour?

The applied voltage strongly influences how thick the oxide layer grows. A higher voltage does not simply produce a darker version of the same colour. It creates a different layer thickness and therefore a different interference colour.

As voltage increases, titanium passes through different colour ranges.

TiHex colours and reference voltages

The values below are the reference voltages TiHex uses for its colour palette. They are not a universal colour standard. Exact shades can vary with alloy, surface preparation, polish, electrolyte, temperature, batch, light source and viewing angle.

Why can the same colour look different?

The perceived colour depends on more than voltage. The underlying surface makes a particularly large difference.

Surface finish

A highly polished surface reflects light differently from a brushed or matt surface. The same anodising setting can therefore look brighter, deeper or softer.

Lighting and viewing angle

Because the colour comes from interference, titanium can look different in direct sunlight and under workshop lighting. Viewing angle also affects how the colour appears.

Alloy and process

Grade 2 and Grade 5 can both be anodised, but may not look identical with exactly the same process settings. Small differences in preparation and bath conditions can also affect the final shade.

Can anodised titanium change colour?

The oxide layer is not paint that can peel off, but its appearance can change through dirt, oil, fingerprints, wear or scratches. Because the layer is very thin, a scratch can alter its optical behaviour locally.

Clean coloured titanium gently with a soft cloth and a suitable, non-aggressive cleaner. Avoid unnecessary abrasion or polishing of an anodised surface.

Is PVD the same as anodising?

No. PVD is a coating process that deposits a separate thin layer on the surface. A PVD colour can therefore have a different appearance and different properties from an anodised colour.

A TiHex finish described as PVD Blue should not be confused with voltage-anodised blue.

Why is exact colour matching difficult?

Parts ordered at different times can show small colour differences. This is inherent to an optical interference process in which preparation and process conditions need to match very precisely.

For the most uniform colours in one visible area, order the required parts in the same colour and, where possible, as one set or batch.

Which colour suits your build?

The choice is mainly visual. Bare Titanium gives a clean, technical appearance. Bronze and Gold are more subtle. Purple, Blue, Pink, Aqua, Teal and Green stand out more in an engine bay or around visible bodywork hardware.

Compare colours on our titanium colours page, then combine your chosen colour with suitable titanium bolts, nuts and washers.

Conclusion

Anodised titanium gets its colour from the interaction between light and a controlled oxide layer, rather than paint or pigment. Voltage is an important process variable, but the final shade also depends on material, finish and conditions.