A bunch of years back I remember one of our crew (and a top bloke as well) summed it up thus:
All silver colours are metalics,ie they are not a solid colour such as white red blue etc.They have small particles of metal that give it that irridesance appearance.Bit like buying a family car in a 'metalic' colour.And as such they all need a coat of clear to prevent oxidation.Clear coats are affected primarily by UV sunlight which tend to break them down and hence tend to dull,craze and discolour.
So at the end of the day anyone who paints a jet silver is a moron.
