San Francisco — Back in the mid-18th century an Englishman named Thomas Whieldon developed and manufactured a heavy lead-glazed pottery called agateware. Looking very much like what the name suggests, the items he produced, mostly teapots, milk jugs, and cow-shaped creamers, were an amalgam of various-colored clays pressed together to form an unlimited number of swirled designs.
Later in his career Whieldon became the partner of Josiah Wedgwood and turned his attention toward porcelains and other more refined types of work. It was not until some 200 years later, thousands of miles from where Whieldon worked, that agateware would be duplicated again.
The successor to Whieldon is a San Francisco potter named Ami Magill. Combining a long interest in antique pottery with a desire to create something different, she decided to specialize in Whieldon's nearly forgotten art.
After doing considerable library research, some with books as old as the original agateware itself, she felt ready to duplicate Whieldon's long-unpracticed methods. ''It was quite a challenge to find the information,'' she says. ''Agateware is not very well known. It's usually just given a slight mention in even the most comprehensive books on English pottery, usually a line or two in the section on Whieldon and Wedgwood.''
Piled about her studio, actually a corner of a huge warehouse in the industrial section of San Francisco, are stacks of thick brown and buff plates, their colors forming the patterns of a marble cheesecake. Among the piles are agateware wall sconces, a tall, gracefully formed vase, and a doorstop in the form of a plump cat. Their colors are various combinations of brown, reddish-brown, buff, and green, glazed in a manner to simulate the now illegal lead glaze that Whieldon and his contemporaries used.
''It is true that I'm copying Whieldon, but it's also true that he was copying the Chinese,'' Ms. Magill says while sorting through some of her plates, no two of which are exactly alike in their agatelike effect. ''A form of agateware actually goes back to the Tang Dynasty, pieces that were found when some of the burial tombs were excavated. During the China trade era, English potters tried to duplicate all the forms of ceramics that they saw coming from China. Whieldon undoubtedly saw some of those Tang pieces and was inspired by them.''
What led to agateware's demise after 40 or so years of popularity was the development of porcelain by manufacturers such as Whieldon and Wedgwood. ''When Wedgwood started making porcelain, all the agateware type of pottery just went out the window,'' Ms. Magill says. ''What was left was shipped to the American market, which was less discriminating than the English. To this day most of the surviving 18th-century agateware is either in this country or in the Victoria and Albert Museum in London.''
Unlike most forms of pottery, agateware cannot be made by being thrown on a potter's wheel. When beginning her work, Ms. Magill takes the various colors of clay, many of which are natural, and slaps them together in a flat oblong piece. Then, after she has rolled them up into a jelly roll-like slab, she slices the clay with a wire. The slices are then pressed into molds, where they are allowed to sit for a half hour. Eight to 12 hours after it has been taken out of the mold, a piece is ready to be fired and glazed.
The chief problem with this method, the same one Whieldon used, is that a lot of the pieces are broken along the way, she says. ''It is more fragile during the production process because the clay isn't all compressed together as it is in other types of pottery. Sometimes it won't come out of the mold. It has to be fired twice and often cracks during the firing process. On average I only end up with about 30 percent of what I started out to make.''
The pieces that do make it through production are quite durable, more durable than machine-made pottery, she says. ''One reason is the sheer weight of it. When it does break, the breaks are usually clean ones that can be easily mended. And because of all the swirls, it is difficult to find the crack.''
Agateware was originally made for use rather than for decoration, and Ms. Magill thinks it is still best enjoyed that way. ''My husband and I have been eating off all sorts of odds and ends of it for years. I find it a pleasure to eat off of because it's so thick and colorful. Lentil soup, for example, is absolutely exquisite when eaten out of an agateware bowl.''
The market for her agateware has been limited. Plates retail for about $30. ''Most of my customers are collectors who are familiar with the history of agateware,'' she says. ''I have made complete dinner sets for people, however, including one that was a service for 12.'' Everything she makes is from custom orders, most of which are placed through the Ronald James china and glassware store at 7415 Sacramento Street in San Francisco.
No matter what she makes, it is all stamped with her personal trademark, a small shell design, on the back. ''I am selling my pieces as reproductions of the earlier pottery, and I don't want there to be any confusion as to what they are,'' she says. ''What I don't want to happen, as so often does with reproductions, is for someone to try to pass them off at auction for the real thing.''
Her concern that this could happen is not unfounded, as china and pottery experts have told her that her work bears an uncanny resemblance to the pieces Whieldon produced. During a recent seminar at the Palace of the Legion of Honor, a San Francisco museum, a china authority from England identified the pieces she brought in to show him as Whieldon. Says Ms. Magill with a grin, ''He was more than a little taken back to learn that a San Francisco potter working in the 1980s had made them instead.''