Ceramics | The Canadian Encyclopedia

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Ceramics

Ceramics are products made from clay (or other nonmetallic mineral compounds) and fired to set the shape. The principal types of ceramic wares are porcelain, which is usually translucent, and stoneware and earthenware, which are opaque.

Ceramics

Ceramics are products made from clay (or other nonmetallic mineral compounds) and fired to set the shape. The principal types of ceramic wares are porcelain, which is usually translucent, and stoneware and earthenware, which are opaque. All three types may be glazed or unglazed; unglazed wares are known as biscuit. Unglazed earthenware is porous and needs glazing to make it waterproof. For potters (as set apart from the ceramic industry) bisquit or bisque refers to the initial firing at low temperature (normally around 900°-1000°C), which allows glazing of the ware. The second, or glaze, firing is much higher for stoneware and porcelain. (Industry may bisque porcelain or earthenware at a higher temperature than the glaze firing to promote strength).

Canadian-made Ceramics

Earthenware utility pottery has been produced by Europeans in Canada since the mid-17th century (and by the Indigenous peoples long before). Utility pottery was the most widely used form of container ware since, being made of local clay, it was inexpensive and readily replaceable. (Hand-blown glass, cast or soldered metalwares and barrels or firkins were considerably more expensive and had fewer uses).

British-made Ceramics

After the British Conquest, 1760, the ceramic wares most generally used in Canada came from Great Britain. Three factors accounted for this situation: Britain regarded its colonies as natural markets for British goods; developments were occurring in the British pottery industry; and British potters promoted their wares aggressively. Canada came under British rule just as British potters were on the verge of making a determined bid for world prominence.

By the mid-19th century, when changes in trade and navigation laws permitted freer entry of foreign goods, the range and variety of British ceramic products was so great and their position so entrenched that Canadians continued to buy them in substantial quantities. In early days, ships' captains were recruited to take out samples and make contacts for future sales; Canadian agents were appointed; some potters journeyed to Canada to assess the market; others opened warehouses in cities such as Québec and Toronto. In 1836 William Taylor Copeland, a prominent Staffordshire potter, became the supplier of ceramic wares to Hudson's Bay Company posts and shops throughout the North-West.

Earthenware

Although, over the years, every thing from pickling pots to ornaments was imported, certain types of British ware predominated in the Canadian market. The first of these popular items was an 18th-century lead-glazed earthenware for the table. Ranging from deep to pale cream in colour, it was called creamware or, after Josiah Wedgwood gained Queen Charlotte's patronage for it in the 1760s, Queensware. Creamware is known to have been used in French Canadian farmhouses, city merchants' homes and government residences.

Early in the 19th century, creamware, its decoration usually hand-painted on glaze, was displaced as the chief tableware by an earthenware of whiter appearance, decorated by a semi-mechanical process called underglaze transfer printing. The technique involved transferring impressions from engraved copperplates to paper and then to the earthenware. It permitted an endless variety of designs (including Canadian scenes) to be printed on tableware at relatively low cost. The glaze over the decoration protected it and gave it brilliance. Hailed as the coming ware by a Halifax importer in 1811, underglaze transfer-printed earthenware became, and remained, the most widely used tableware in Canada.

Another British development important in the Canadian trade had to do with the earthenware body, as distinct from its decoration. In 1813 Charles James Mason, a Staffordshire potter, patented a tough, high-fired earthenware called ironstone china. Scores of British potters copied Mason's product, marketing it under many names (stone china, opaque china, etc) and offering it painted, printed or plain. Its durability, and the cheapness of the undecorated variety, ensured sales in a pioneer country such as Canada.

Porcelain

Porcelain was never imported in the same quantities as earthenware, although there had always been some supplies of this more expensive ceramic product. In 1793, for example, Worcester porcelain was being offered in Saint John, NB, in exchange for furs if cash was not available. Eighteenth-century English porcelains were apt to be capricious in the kiln. The invention, towards the end of the century, of what is now called English bone china (basically, a composition of china clay, china stone and a high proportion of bone ash) cut kiln losses and ensured wider sales of British porcelain in Canada. By Victorian times, virtually every British porcelain manufacturer had switched to a bone formula.

Victorian times also brought an unprecedented taste for what a Toronto importer called "articles to fill a space and gratify the eye." Of the ceramic ornaments that poured from Britain's potteries into Canadian homes, none had a greater appeal than those in Parian, a porcelain invented in Staffordshire in the 1840s and named after marble from the Greek island Paros. Its avowed object was to simulate marble. Busts, eg, of Sir John A. Macdonald and Edward Hanlan (the Toronto oarsman who became world champion in 1880), were produced in Parian.

Canada never developed a pottery industry that seriously challenged imported tablewares or ornaments. As Canadian potters turned out more and more of the common, dark-bodied earthenwares and stonewares for kitchen or storage use in the second half of the 19th century, imports of these wares dwindled. However, by that time Canada's population was expanding rapidly and the demand for finer wares was increasing in proportion. British potters continued to have a market that saw at least some of their products in every home in Canada.

ELIZABETH COLLARD

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Earthenware

Produced from indigenous, red firing clays, earthenware was formed into various types of vessels. Earthenware production required raw natural clay, which was liquefied, screened to eliminate grit or other intrusions and redried to a more plastic consistency. To assure uniformity between pieces, clay for the wheel was often measured by weight. As the potter produced each vessel on the wheel, it was taken out for air drying to evaporate all possible water (potters had to watch the weather while drying finished pots). Dried pots were stacked into a wood-fired kiln for firing. The process required care, for a kiln load could represent a month's production.

Firing was done with dry wood in fireboxes surrounding the kiln. Often a firing lasted 2-3 days, after which the kiln was cooled gradually, as the pottery could crack if this were too rapid. Pottery was then glazed by dipping in the glaze mixture; for interiors, glaze was poured in, swirled around and poured off. The glaze (usually a lead-oxide, clay and silica mixture in water) was allowed to dry, and the pots were again kiln-stacked and refired to fuse the dried glaze.

Stoneware

Stoneware was first produced in Canada in 1849 using clays imported from Amboy, New Jersey. In form and fabrication technique, Canadian stoneware was identical to American stoneware of the same period, and many of the early producers had come from American potteries. The expensive (because of freight costs) New Jersey clay was fired at a temperature of about 1200°C. In Canada it was often "bulked up" with local earthenware clay, which reduced its effective firing temperature.

Stoneware, fired at much higher temperatures than earthenware, is a vitrified pottery, ie, waterproof in an unglazed state. Glazing was often done by throwing salt into the kiln at maximum firing temperature. The salt (sodium chloride) volatilizes; the sodium combines chemically with the silica to form a sodium silicate glaze (ie, a form of glass). Generally, the chlorine combines with water vapour in the air to form hydrochloric acid vapour, but in some instances of very low humidity may escape as deadly chlorine gas. Because of its vitrified structure, glazed stoneware is less fragile than red earthenware. The sodium silicate glaze, in chemical combination with the pottery body (rather than an overlaid layer as the glazes on earthenware), is insoluble and impervious to acids or alkalis.

A Canadian source of stoneware clay was not discovered until the late 19th century, when a deposit was located along the Shubenacadie River, NS. The clay was used by the Enfield pottery. Another major source of stoneware clay in Canada is Abbotsford BC, once used by the former Medalta Pottery, Medicine Hat, Alberta.

Production of stoneware required a more sophisticated technology than earthenware. Once formed into vessels, stoneware was typically stamped (using printer's type) with either the maker's name or that of a commercial purchaser. The pottery was dried and often decorated before firing with designs in cobalt-oxide blue, referred to as powder-blue in potters' glaze recipes. Cobalt was the primary glazing oxide used for decoration, as it alone remained unaffected by varying firing atmospheres and could be relied on for providing a stable, blue colour. The designs ranged from simple brushed-on floral motifs to elaborate incised or glaze-trailed figures or scenes.

Because of its durable body and impervious glaze, stoneware was preferred to cheaper, lead-glazed earthenware for food preparation and storage, especially pickling or salting. However, by the last quarter of the 19th century, a gradual shift of food preparation, from the home to the processing plant, began, and refrigeration, commercial canning and dairy processing began to erode the market for the utility pottery necessary for home processing. In the 1880s, mass-produced, inexpensive glass provided the advantage of visible contents and further reduced the pottery market. By the late 1880s the number of pottery operations in Canada was declining and, because of accelerating changes in food preparation and marketing, most potteries closed between 1890 and 1910.

Archaeological investigations of early potteries indicate that firing accidents were common: great quantities of "waster" pottery were discarded. Before the 20th century, potters had little knowledge of the components of their clays and only rudimentary means of measuring kiln temperatures. In small local potteries, an average loss of some 50% of production seems a realistic estimate. Prior to the 20th century, Canadian earthenware pottery followed 4 basic regional forms:

Québec Pottery

Québec pottery, the earliest type, was produced from the mid-17th century to the early 20th century. Although the earliest Québec pottery was established in 1655, New France imported French earthenware until 1760. These imports consisted primarily of basic bowls, pitchers and jugs glazed with a green, copper-oxide glaze. Québec potters emulated the forms but not the colour of French ware. Their pottery usually had a transparent lead-oxide glaze, sometimes over a brown slip coating which covered the pottery body. Québec pottery was not decorated in the 18th century; in the 19th century, a simple American decoration of spatterings of brown slip was adopted.

Maritime Pottery

Maritime pottery, particularly that of NS and PEI, was basically northern English and Scottish in design derivation. Earthenware was not produced in the Maritimes before the early 19th century and, with rare exceptions, was produced in limited variety. Maritime earthenware was based on the dense iron-rich clays of the area and fired to a dark red. The interior lining of vessels and the sparse decoration made use of white slip, made of fine white clay from the Magdalen Islands. The most common items are crocks and large bowls with deep-red bodies, interiors coated in white slip and transparent lead-oxide glazes.

Upper Canada Pottery

Upper Canada pottery shows various ethnic influences, the strongest being that of the Pennsylvania Deutsch (Germans) who had migrated into the region. Ontario Germanic pottery is characterized by a wide variety of forms and shapes and, often, by imaginative and colourful uses of coloured clay slips and different metallic-oxide glazes (eg, copper, iron and manganese, as well as lead). Glaze colour, pattern and variation are infinite, as are vessel forms. Most potters produced primarily basic utility and container vessels, but they also made slipcast wares, molded figures, miniatures, toys, and gift and presentation pieces. The earliest pottery in the region was established in 1794; unlike the situation in Québec and the Maritimes, potteries proliferated because of isolation and the difficulty of receiving British imports.

Generic North American Pottery

Generic North American pottery, eg, slip-cast tablewares, canning vacuum jars and short-term fashions like the "rustic" wares of the 1880s, appeared and became universally popular after regional distinctions began to disappear about 1870. The influence of widespread advertising and the appearance of mail-order catalogues very quickly outweighed regional tradition, not only in pottery but in all decorative art forms. The age of the individual craftsman was effectively giving way to the age of the machine and the factory.

Little early pottery is known from west of Ontario because, by the time European settlement began in the late 19th century, the domestic use of handmade earthenware was declining. A pottery was established in Winnipeg in the 1880s. Evidence provided by industrial archaeology studies indicates that it produced only utility wares. Later, stoneware potteries (notably Medalta Pottery) were established at Medicine Hat and nearby, producing stoneware from local clay discovered about 1910.