Having researched this for the Abbot, it's quite interesting. The original fire-resisting aluminium paint to DEF STAN 80-9/1 is more aluminium particles in suspension than a normal paint. You don't seem to be able to buy it any more but Clive managed to find me a couple of old tins.
It doesn't fade as such, just gradually forms a dull oxidised surface layer, which has a nasty habit of rubbing off on skin or clothes. When first applied it is very, very shiny!
Andy