'It is the pot that tells me what I want to do' states Carol Rossman when asked for the origins of her complex burnished and glazed raku work. Rossman's reputation is founded on the accuracy of her geometry-based patterns and the control of a superb range of colour in the notoriously uncontrollable technique of raku. Repeat patterns to paisleys, art deco to aboriginal, her designs reflect a myriad of sources that she orchestrates into her own particular voice. When pushed further about her work she states that she looks for the contrasts to guide her ­ soft to hard, straight to curved, voluptuous to angled ­ these things speak to her.

Rossman chooses her plate, bowl and vessel forms with little or no extraneous detail, from a vocabulary of simple classically shaped forms she has developed over her 20-year career. The forms are thrown with a white raku clay body that was developed by fellow Canadian, Michael Sheba. From the beginning Rossman knows where the design will be placed inside, outside or on both surfaces. Her designs require a smooth skin, so she trims her leatherhard pots and then slightly burnishes them with a rubber or metal rib. When there is no interior decoration on the piece she will leave throwing rings on the inside only as a reminder of the artist's touch. A rich shiny black surface is used to set off her designs and when the pots are bone dry, half strength terra sigillata is applied with a large brush. Experimentation was required before the right thickness was achieved. Burnishing is then applied to the terra sigillata until the surface feels smooth like satin.

Rossman finds that burnishing with plastic credit cards or plastic-coated playing cards producse the best surface results. When completely dry, the pots are bisqued fired to cone 08. She studies the bisqued pot and decides intuitively whether the design will be freeform or repeat pattern, and how many repeats are necessary. A design can be lightly sketched in on a section of the white bisque ware with an ordinary pencil, while corrections are made with a technical eraser. For ease of correction Rossman suggests not to erase along the line but across the pencil line to prevent rubbing the graphite into the surface. When the basic repeat of the pattern is satisfactory, a protractor is used to divide the pot into equally spaced sections. For designs on the interior, sections are marked from the centre to the rim; for the exterior, the rim to the base. To ensure accuracy in the repeats it is necessary to draw straight lines over the curving surfaces of the pots. Rossman attaches ordinary masking tape and then draws her guidelines with a lead pencil.

All areas that will not be glazed on the pots must now be masked with tape. Rossman uses black Chartpak Crepe tape to create her designs. She settled on this product because the tape stretches making it easy to follow the complex curves that so often make up her designs. This product also comes in a wide variety of widths so that several line widths, from fine to thick can be used in any one design. At first only one section of the design is taped. As the tape is black, this allows Rossman an opportunity to see the effect of the design on the form, the tape representing the areas of smoke and the white, the glazed portion.

Any improvements in the balance of pattern can be easily corrected at this time. With the design sections already established, the remaining pattern repeats are taped. While the repeats look exact, Rossman eyeballs the design while she tapes each section. This gives a subtle variation to the piece and keeps the design from appearing mechanical. The rim is rarely glazed so it and the bottom of the pot are the last areas taped. To simplify the glazing process and to save tape on pieces where there are large areas of undecorated clay, these areas can be masked with plastic wrap such as recycled dry cleaning bags. After the final layer of glaze is applied, all the tape is removed with the aid of dental tools and tweezers.

Glazing

The process of glazing begins with Rossman studying the taped piece to see if there are areas on the pot that she wants to highlight with different glazes or subtle colour changes created by oxides. Rossman has reduced her stable of glazes (having used more than 30 different glazes over the years) down to 12 which are used in combination with seven oxides. Her experimentation over the years has given her the knowledge of glaze combinations so that, in the end, a pot may have up to six layers of glaze and oxides to create the rainbow effects that identify her work. On the bare pot, areas are picked out for highlighting by painting sometimes up to three layers of glaze or oxide with the appropriate sized brushes. These highlighted areas may be random but more often they are chosen to create a repeat pattern to give movement to the design. After the final choice of how many areas are accentuated in different glazes, the pots are air brushed with an even coat of glaze. Then this coat may have other layers of glaze sprayed on to give the surface even more movement with lively colour changes on the surface. For a subtle effect used occasionally, the entire piece is lightly sprayed with glaze while slowly rotating it on a banding wheel; this lowers the contrast between areas. All work must now be dried for at least two days before firing.

Glaze Firing

One rule of firing that Rossman insists upon is the need to raku with at least another person or two. While safety is the main concern here, the social aspects of the exchange of ideas are a welcome change from the solitary aspect of the studio. The firings are done on an as-needed schedule though Rossman says that warm dry overcast days are her favourite. She favours a brick raku kiln and at home she uses a standard top-hat brick and metal drum kiln fired with propane to cone 08. While firing, time is spent preparing the reduction bins to her specific requirements.

Post Firing

In order to maximise reduction, the post-firing bins are filled with sawdust to minimise the air space between the pot and the combustible materials. The sawdust is levelled and then covered with one sheet of newspaper to keep the sawdust from flying around during reduction. On the centre of the newspaper sheet Rossman puts a piece of wood at least as large as the pot bottom. Any wood will do and Rossman often collects scraps from building sites. She uses a wood base instead of a firebrick for the reduction it creates on the bottom of the piece. Finally, the bin is lined with rolled newspaper wrapped around the interior circumference. Great care is taken so that when the fired pot is placed in the bin it sits only on the block of wood and no newspaper comes in contact with the surface. Through trial and error Rossman prefers using the Sunday New York Times though she is not certain whether it is the paper or the ink that makes the difference.

The fired pot is carefully lowered into the bin with tongs on to the wooden block. The lid is not placed on the drum until big healthy flames lick the pot. The piece remains covered until the smoke has almost dissipated. At this point Rossman lifts one side the lid slightly to create uneven oxidation on the piece. This 'burping' of the bin is one more chance to add to the variations of the surface so that when one looks at the piece, every side of the pot reveals a different aspect. The pot now is left to sit in the closed bin for at least 20 to 30 minutes until she can pick it up with gloves. The piece is then left to cool to ambient temperature and shelved for two to three days. Pieces are then examined for soot markings. Many of Rossman's surfaces are dry or matt glazes, so the soot is removed gently with a toothbrush. On the blackened inside of the pot, soot can be easily removed with a dry cloth. After a final examination of the surfaces, Rossman buffs the pot with a silicon-impregnated sponge used to shine shoes. This final buffing brings the smoked terra sigillata up to a rich black that sets off the multi-coloured veils of colour.

Jonathan Smith, MFA (Chicago), is the Curator of the Collection at the Burlington Art Centre, Burlington, Ontario, Canada, home of the largest permanent collection of contemporary Canadian ceramics. Caption title page: Carol Rossman in her studio. Photographs: Michael Dismatsek and Jonathan Smith.