As above, its used primarily, along with the other glazes that companies like AV (Vallejo) make to influence the final colour of the area. For example, using the woodgrain glaze from Vallejo on a piece of beige/white painted miniature would give it a colour and \'look\' that is characteristic of wood. Using the red glaze or orange or such over the top of metal gives you a rusty appearance. So to answer your question its a translucent colourant intended to weather areas, be they clothing or metal or whatever - in effect, its similar to the antiquing colours used by furniture repairers or restorers to give the piece a particular look and feel.