Gilding
Water-gilding dates from the time of the ancient Egyptians, who used it to decorate - amongst other things - the sarcophagi in which they interred their Pharoahs. The techniques they used for preparing the surface and laying on the gold are largely unchanged from those days. The gold we use is mainly 23.5 carat - pure gold is 24 carat - but we also use various alloys, such as 'red' gold (which has copper in it) or 'white' gold (which has silver added). This tarnishes slowly, and the effect can be wonderful. It can also be unpredictable!
There are other alloys and metals that we use: silver, 'grey' gold, caplan and platinum for instance. This latter has a wonderful soft colour, not unlike a very gentle gold. All these are laid onto a clay surface, called 'bole', which comes in a range of colours and which can be mixed to give - or match - a specific colour. Water-gilding can be burnished or left unburnished, giving a wonderful contrast between the shine of the former and the matt effect of the latter. Oil-gilding - where the gold is fixed to a surface by a slow-drying adhesive called 'size' - is uniformly matt, as it is not possible to burnish gold laid by this method.
Although gold is bright, and renowned for its brilliance, it doesnt have to be garish; toned glazes can be used to 'antique' it and give the innocent eye the impression that it's been there for years!