How a bronze patina is applied
A bronze patina can be almost any colour. When my sculptures are well patinated the surface takes on a depth and weight which suits my work, because I like the forms I make to feel heavy and have substance. Sometimes my original ceramic figures gain that heavy look - but only after years of weathering in the garden so that lichen and moulds can flourish on the surface. It's not that easy with bronze, and patination is a highly skilled process. My bronze sculptures are patinated by the man who also casts my work. Tiny changes in the chemicals used, the exact composition of the bronze and the temperature when the chemicals were applied can all affect the end result.
To apply a bronze patina, the piece is coated with chemicals mixed to a recipe that will produce the colour I've chosen. Usually the sculpture will then be heat-treated, although a patina can be applied cold. Finally, the surface is 'fixed' with wax, lacquer, or for my work, both, to protect the colour. Even so, the colour of a bronze patina does change over time, sometimes intangibly. It might get deeper or even be altered dramatically by the elements or any substance that touches it. That's the main reason why people are asked not to touch bronzes on public display - because grease or dirt from their hands can affect the patina. Personally, though, I think that gentle touching of the surface can improve the look of a bronze, since people tend to touch the high points, and you can end up with a more three-dimensional look.
If this happened, or the patina changed in any other unwanted way, the piece could be repatinated. This is a big undertaking, since the sculpture has to be cleaned of all previous chemicals and thoroughly sandblasted. Then new chemicals are applied according to the recipe for the colour required. If at the end of the process the bronze patina still isn't correct, it all has to be done again from scratch. Most of the time I choose a mid-tone for my work - about the density of damp clay. A bronzey colour like the one used on Flip might seem to be more 'natural', but this still has chemicals applied to soften the colour and give definition, and the final colour has also been fixed with wax and lacquer. Sometimes I choose a soft stoney colour, as on Round Face, (below, centre) sometimes a darker, denser colour, as on Large Mother and Child (below, left and right.
Patination can alter the mood of a sculpture, enhance its readbility (the way people read the surface to understand what the form is doing), or conversely make it more difficult to read and understand. There are three main aspects of a bronze patina - the colour, the evenness and the tone. Larger sculpture with a smooth surface, like Morning, can cope with a patina which is more varied. A small more detailed piece like Hug needs a more uniform patina. Back to top of Bronze Patina. Read more about how a sculpture is made. |
