When applying the over glaze decoration,we must go through the process of decoration firing before the over glaze pigments are fully developed and blended with the glazed coating.Charcoal is the main fuel in the traditional decoration firing.A decoration firing furnace has two components.The inner component is a large and round sagger with a vortex sagger cover on the top, which has a round hole as an observation hole. It looks like a deep tube.Four refractory bricks are laid on the bottom of the sagger. There is a certain distance between the outer surface of the large sagger and the circle wall made of refractory brick.There are a number of holes on the bottom (The number of holes depend on the size of the furmace and the holes are locally called "fire holes".Workers use the holes to remove charcoal out of the furnace for cooling.Porcelains are loaded and fired in the large sagger and charcoal is put into the separation between the sagger and the outer refractory bricks. The separation is locally Called "fire chamber".At the initial stage of firing,it is not beneficial to seal the furnace in order for the volatilization of moisture.The heat-up rate depends upon the sizes and numbers  of  wares in the sagger.The rate should be slower for the large or thick-bodied wares,or rapid for small and thin bodied ones.The firing conditions in the furnace can be observed through the hole on the cover in the course of firing.As the temperature increases,the wares will gradually become redder and slowly become more obscure.When the forms of wares slowly become clearer and the wares present light orange in color,it is the time to stop firing and cool the wares in a natural way.By contrast,the cooling time for Gucai and Fencai is longer than that of grisaille painting and polychrome painting.It also careful undertaking to load the decoration firing furnace(i.e. loading a kiln).The common way is to load larger wares before small ones.When loading the co1ored wares or wares with gilt lacing,the inverted bowl method should be applied for it saves space and will not damage the golden lines and colors.The furnace should neither be too full,nor too empty ．

Today, the decoration firing furnaces in Jingdezhen have been changed to electric kilns on the whole. It is more convenient for firing.The points for attention in the process of loading.unloading.firing and cooling are basically similar to those of the traditional charcoal kilns ．