Most aluminium items are anodised.
- The resulting surface from anodising, is harder than original aluminium
Often used when aluminium is used outdoors e.g. window frames, architectural features. - Surface is also more resistant to corrosion
- Colour of anodising depends on chemicals used in the process
some colours are more lightfast than others.
Common colours are:-- Black
- Silver
- Gold
- Green
- Blue
- Red
Various shades of colours are produced with varying the anodising chemicals and conditions
- Laser engraving of the surface removed the anodising and replaces with a white aluminium oxides
As a result of engaving the image shows up as white. This is most dramatic with darker colour surfaces.
In case of lighter colours and particularly silver the lower contrast results in beautiful soft effect. often related to wedding items
Another form of aluminium commonly seen is coated or powder coated aluminium
When engraved the coating is removed leaving white / silver image with pleasing results
Polished and Brushed Aluminium ( no anodised surface )
Laser will mark this surface with a crisp black image.
This is achieved by coating with chemically active coat, then fusing this to the metal with laser. Excess coating is washed off the surface leaving black image where laser has reacted and bonded this with the metal.