Decorative and finishing techniques

For aesthetic reasons articles can be decoratedSgraffito involves scratching through a layer of
by a large variety of techniques , including thecoloured slip to reveal a different colour or the
application of colours and designs. Decoration canbase clay underneath. If done carefully, one colour
be:of slip can be fired before a second is applied prior
In the bodyto the scratching or incising decoration. Often slips
On the surface of the body but beneath theengobes used in this process have a higher silica
glaze, underglaze decorationcontent, sometimes approaching a glaze recipe.
In the glazeThis is particularly useful if the base clay is not of
On the surface of the glaze, on-glaze decorationthe desired colour or texture.
Additives can be worked into moist clay body,Banding, is the application, by hand or by machine,
prior to forming, to produce desiredof a band of colour to the edge of a plate or cup.
characteristics to the finished ware. VariousAlso known as lining
coarse additives, such as sand and grog (fired clayLitho, is a commonly used abbreviation for
which has been finely ground) to give the finallithography although alternatives names of
product texture, and contrasting colored clays andtransfer or decal or used. These are used to
grogs result in patterns. Colorants, usually metalapply designs to artciles. The litho comprises three
oxides and carbonates, are added singly or inlayers: the colour, or image, layer which comprises
combinations to achieve a desired colour.the decorative design; the covercoat, a clear
Combustible particles can be mixed with the bodyprotective layer, which may incorporate a
or pressed into the surface to produce texture.low-melting glass; the backing paper on which the
Agateware A long established technqiue is todesign is printed by screen printing or lithography.
partially mix different coloured clay bodies to giveThere are various methods of transferring the
a distinctive 'mottled' decoration. In Great Britain,design while removing the backing-paper, some of
these techniques are known as agateware, afterwhich are suited to machine application
agate stone which shows similar colour banding,Gold, decoration with gold is used on some high
whilst in Japan a similar technqiue is called "neriage.quality ware. Different methods exist for its
An analogue of marquetry can also be made, byapplications, including:
pressing small blocks of coloured clays together,Best gold - a suspension of gold powder in
and using the resulting mosaic to create distinctiveessential oils mixed with a flux and a mercury salt
patterns. To ensure the final articles are unfaultedextended. This can be applied by a painting
care is needed with selection to choice differenttechnique. From the kiln the decoration is dull and
bodies of compatible shrinkage and thermalrequires burnishing is reveal the full colour
expansionAcid Gold – a form of gold decoration
Burnishing, like the metalwork technique of thedeveloped in the early 1860s at Mintons Ltd.,
same name, involves rubbing the surface of theStoke-on-Trent, UK. The glazed surface is etched
unfired article with a suitable tool, typically ofwith dilute hydrofluoric acid prior to application of
wood, steel or stone, to give a smooth, polishedthe gold. The process demands great skill and is
surface which remains even after firing. Finerused for the decoration only of ware of the
clays give a smoother, shinier surface thanhighest class.
coarser clays, as will allowing the pot to dry moreBright Gold – consists of a solution of
before burnishing although that risks breakagegold sulphoresinate together with other metal
An ancient Armenian urn.Engobe, to give a finerresinates and a flux. The name derives from the
surface, or a coloured surface, slip can be coatedappearance of the decoration immediately after
onto the leather-dry body. Slip produced to aremoval from the kiln as it requires no burnishing
specific recipe is sometimes called an engobe. SlipsMussel Gold – an old method of gold
or engobes can be applied by painting techniques,decoration. It was made by rubbing together gold
or the piece can be dipped for a uniform coating.leaf, sugar and salt, followed by washing to
Many pre-historic and historic cultures used slip asremove solubles.
the primary decorating material on their ware.