A slip is a clay

slurry A slurry is a mixture of denser solids suspended in liquid, usually water. The most common use of slurry is as a means of transporting solids or separating minerals, the liquid being a carrier that is pumped on a device such as a centrifugal pu ...

used to produce

pottery Pottery is the process and the products of forming vessels and other objects with clay and other ceramic materials, which are fired at high temperatures to give them a hard and durable form. Major types include earthenware, stoneware and por ...

and other

ceramic A ceramic is any of the various hard, brittle, heat-resistant and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature. Common examples are earthenware, porcelain ...

wares. Liquified clay, in which there is no fixed ratio of water and clay, is called slip or clay slurry which is used either for joining

leather-hard In pottery, leather-hard is the condition of a clay or clay body when it has been partially dried to the point where all shrinkage has been completed, and it has a consistency similar to leather of the same thickness as the clay. At this stage, th ...

(semi-hardened) clay

body Body may refer to: In science * Physical body, an object in physics that represents a large amount, has mass or takes up space * Body (biology), the physical material of an organism * Body plan, the physical features shared by a group of anima ...

(pieces of pottery) together by slipcasting with mould, glazing or decorating the pottery by painting or dipping the pottery with slip.What is slip in pottery
thepotterywheel.com, accessed 10 July 2021. Pottery on which slip has been applied either for glazing or decoration is called the slipware. Engobe, from the French word for slip, is an

American English American English, sometimes called United States English or U.S. English, is the set of variety (linguistics), varieties of the English language native to the United States. English is the Languages of the United States, most widely spoken lan ...

term for materials similar to a slip, though the definition seems variable. Some American sources say it is synonymous with slip, and use it in preference to "slip", while others draw distinctions, mainly in terms of engobe using materials other than clay. On one definition engobe, as compared to slip, has somewhat lower clay content, higher proportion of

flux Flux describes any effect that appears to pass or travel (whether it actually moves or not) through a surface or substance. Flux is a concept in applied mathematics and vector calculus which has many applications to physics. For transport ph ...

, and added filler, and in some cases a colorant. It is mostly used in relation to contemporary pottery, but sometimes for slip in historical contexts.

Usage of slip

Joining and molding

An additive with

deflocculant Flocculation, in the field of chemistry, is a process by which colloidal particles come out of suspension to sediment under the form of floc or flake, either spontaneously or due to the addition of a clarifying agent. The action differs from p ...

properties, such as

sodium silicate Sodium silicate is a generic name for chemical compounds with the formula or ·, such as sodium metasilicate , sodium orthosilicate , and sodium pyrosilicate . The anions are often polymeric. These compounds are generally colorless transparent ...

, can be added to the slip to disperse the raw material particles. This allows a higher solids content to be used, or allows a fluid slip to be produced with a minimal amount of water so that drying shrinkage is minimised, which is important during slipcasting. Usually the mixing of slip is undertaken in a

blunger A blunger is a machine commonly used in the pottery industry for mixing slip, a mixture of clay and water. A blunger usually consists of a round or octagonal tank with a mixer. Clay is added to the water-filled blunger and then mixed into a slurr ...

although it can be done using other types of mixers or even by hand. * To join sections of unfired ware or greenware, such as handles and spouts. * To fix into place pieces of

relief Relief is a sculptural method in which the sculpted pieces are bonded to a solid background of the same material. The term ''relief'' is from the Latin verb ''relevo'', to raise. To create a sculpture in relief is to give the impression that the ...

decoration produced separately, for example by moulding. This technique is known as ''

sprigging Sprigging is the planting of sprigs, plant sections cut from rhizomes or stolons that includes crowns and roots, at spaced intervals in furrows or holes. Depending on the environment, this may be done by hand or with mechanical row planters. Spri ...

''; an example is Jasperware. * When slip is used to join two pieces of greenware together, it is generally used with a technique known as scratch and slip, whereby the contact points on both pieces are scored with multiple criss-crossing lines and slip painted on one piece over the scores.

Decoration and protection

Charger of Charles II in the Boscobel Oak LACMA M

Slipware is pottery decorated by slip placed onto a wet or

clay body surface by dipping, painting or splashing. Some slips will also give a moderate degree of the hardening effect, and decreased permeability, that a

ceramic glaze Ceramic glaze is an impervious layer or coating of a vitreous substance which has been fused to a pottery body through firing. Glaze can serve to color, decorate or waterproof an item. Glazing renders earthenware vessels suitable for holding ...

would give. Often only pottery where the slip creates patterns or images will be described as slipware, as opposed to the many types where a plain slip is applied to the whole body, for example most fine wares in Ancient Roman pottery, such as

African red slip ware African red slip ware, also African Red Slip or ARS, is a category of ''terra sigillata'', or "fine" Ancient Roman pottery produced from the mid-1st century AD into the 7th century in the province of Africa Proconsularis, specifically that part r ...

(note: "slip ware" not "slipware"). Decorative slips may be a different colour than the underlying clay body or offer other decorative qualities such as a shiny surface. Selectively applying layers of colored slips can create the effect of a painted ceramic, such as in the

black-figure Black-figure pottery painting, also known as the black-figure style or black-figure ceramic ( grc, , }), is one of the styles of painting on antique Greek vases. It was especially common between the 7th and 5th centuries BCE, although there are ...

red-figure pottery Red-figure vase painting is one of the most important styles of figural Greek vase painting. It developed in Athens around 520 BCE and remained in use until the late 3rd century BCE. It replaced the previously dominant style of black-figure vas ...

styles of

Ancient Greek pottery Ancient Greek pottery, due to its relative durability, comprises a large part of the archaeological record of ancient Greece, and since there is so much of it (over 100,000 painted vases are recorded in the Corpus vasorum antiquorum), it has exe ...

. Slip decoration is an ancient technique in Chinese pottery also, used to cover whole vessels over 4,000 years ago. Principal techniques include slip-painting, where the slip is treated like paint and used to create a design with brushes or other implements, and slip-trailing, where the slip, usually rather thick, is dripped onto the body. Slip-trailed wares, especially if Early Modern English, are called slipware. Chinese pottery also used techniques where patterns, images or calligraphy were created as part-dried slip was cut away to reveal a lower layer of slip or the main clay body in a contrasting colour. The latter of these is called the "cut-glaze" technique.Vainker, 116-117 Slipware may be carved or burnished to change the surface appearance of the ware. Specialized slip recipes may be applied to biscuit ware and then refired. Barbotine (another French word for slip) covers different techniques in English, but in the sense used of late 19th-century art pottery is a technique for painting wares in polychrome slips to make painting-like images on pottery.

Other uses in pottery

A slip may be made for various other purposes in the production and decoration of ceramics, such as slip can be used to mix the constituents of a clay body.

Gallery

File:MET DP274692.jpg, Chinese

Cizhou ware Cizhou ware or Tz'u-chou ware () is a term for a wide range of Chinese ceramics from between the late Tang dynasty and the early Ming dynasty, but especially associated with the Northern Song to Yuan period in the 11–14th century. It has been ...

vase with cut-glaze decoration File:Phenician plate with red slip 7th century BCE excavated in Mogador island.jpg,

Phoenicia Phoenicia () was an ancient thalassocratic civilization originating in the Levant region of the eastern Mediterranean, primarily located in modern Lebanon. The territory of the Phoenician city-states extended and shrank throughout their histor ...

n plate with red slip, now wearing away, 7th century BC File:Miletus ware showig red clay base.jpg,

Miletus ware Miletus ware is a type of pottery that was produced in various locations in Anatolia between the late 14th and mid 15th centuries. The pottery was discovered through excavations in the 1930s by Friedrich Sarre at Miletus, hence the ware's name. Th ...

showing a red body covered by white slip, then painted in blue, c. 1400,

Turkey Turkey ( tr, Türkiye ), officially the Republic of Türkiye ( tr, Türkiye Cumhuriyeti, links=no ), is a list of transcontinental countries, transcontinental country located mainly on the Anatolia, Anatolian Peninsula in Western Asia, with ...

References