Compléter Glazing and FiringVersion en ligne Fill in the blanks to test your knowledge par kayn Lewis 1 colours Glazes Pit biaxial reduction silica heatwork organic stilts biscuits Saggar Raku Smoke Bisque Pyrometric oxidation Stoneware batt Earthenware triaxial ceramic Work is put through a first firing , typically 1000°C , called a Firing - that is followed by a subsequent glaze firing . This turns it into , a clay that has been fired high enough that it can no longer be recycled into wet clay . can be sprayed , poured or dipped , and when fired produces an impervious glass like surface . Testing glazes using and blends can help adjust recipes . Glaze firings happen at two temperature ranges - Low fired usually under 1200°C , with high porosity ( Porous ) and a separate glaze layer over the body . is called . High fired usually above 1200°C , with low porosity ( Not Porous ) and an integration of the glaze and the body is called . cones are used to check the inside the kiln . Shelves are prepainted with wash / kiln wash to protect them from glaze drips . Work can be placed on so a glazed surface does not touch the kiln shelf , work may also be placed on small prefired clay slabs ( ) or over sand ( which can also be used under large pieces where shrinkage could cause cracks , to enable some movement ) to protect shelves further . A firing is used to control the amount of oxygen around work during firing . In a reduced atmosphere oxygen within the glaze is drawn out this affects the that can be achieved ( copper changes from green to red ) . When oxygen levels are not reduced the firing is called an firing . Some alternative firings are done at a lower temperature , fired in an outdoor gas kiln and instead of allowing work to cool down in the kiln , it is taken out while hot . Low fire glazes are used in a firing where work is cooled quickly in the air . It can also be sprayed or submerged in water while hot , or placed in combustible material like wood shavings or sawdust , this has a localised reaction similar to the gas kilns reduction firing , firing is when hot pieces are placed in metal bins of combustible material ( wood shavings and newspapers ) and colourants ( optional ) . The porous nature of the low fired clay allows patterns to be absorbed into the surface . In a combustible firing work can also be wrapped in combustible material , and then in clay boxes , aluminium foil , or newspaper . This container is called a . An outdoor firing in a hole filled with combustible material and left overnight to smoke is called a Firing . Low fired Porous ceramics take on designs from the smoke absorbed and reactions with combustibles including materials and colourants .