How are the different colors achieved?
Anodizing does not involve any dyes. The color on the surface is apparent because light reflects through the created oxide layer to create a color. Without the presence of light that color wouldn’t be there.
Light reflects off of the surface of titanium. When a piece is high polished and not anodized, it reflects its mirror finish. When a piece is anodized, the light has to reflect off of the surface through the added oxide layer. The oxide layer filters the light waves passing through it and causes interference in the light reflected. This causes the light to reflect in a color.
The color that is apparent on an anodized piece of titanium depends on the thickness of the oxide layer that has been applied to it. The thickness of the oxide layer that is formed during the process depends on the voltage of electricity that has been that has been applied to it.
If you are anodizing more than one piece and you want them to be the exact same color, it would be a good idea to anodize them all at the same time. You may not get a color match if you do them on separate occasions.
Thicker and/or larger pieces to be anodized may take longer and sometimes increased voltage, to achieve a similar color to their thinner, smaller counterparts.
Which voltage achieves which color?
The more voltage that is applied during the process, the thicker the oxide layer that is achieved. The voltage range used in this type of anodizing is usually between 15-120V. The colors are in approximate ranges, and will differ slightly for each set up. It is good to start a little lower and turn it up gradually.
This chart represents the voltage ranges that I use. I can usually achieve the color I am after within these ranges, however I always start out lower and work my way up.?You can change the color of an anodized piece to another color of a higher voltage. It is possible, for instance, to turn a dark blue anodized piece to light blue, yellow, or to any of the colors of a higher voltage. It is not possible, however, to turn that dark blue piece to a purple or a copper color. If you wanted to do that, the oxide layer would have to be stripped off through polishing/steam cleaning.?The quality and consistency of the oxide layer formed, largely depends on the quality of the surface finish. When we anodize a piece of jewelry to be sent out to a customer, we sometimes do not get the result we want on the first try. The piece then gets re-polished and steam cleaned, to be anodized a second time. It might be a really good idea, if you are planning to anodize jewelry yourself, to get a polishing wheel and a steam cleaner.