The Story of Porcelain Part 23

"That is one of the difficulties our designers encounter, too,"

replied Mr. Marwood. "Sometimes you will see pieces where the s.p.a.cing is not equal, or where a border does not join. That indicates inaccurate placing of the pattern, or an incorrect estimate of the s.p.a.ce."

"I don't wonder they get it wrong sometimes," declared Theo. "It isn't so easy. I remember once decorating a card for Mother with some decalcomania pictures. It was mighty hard to get them where I wanted them."

"Decalcomania?" exclaimed Mr. Marwood. "We do that kind of work here too. In fact, a great many of our most beautiful gold borders are transferred to the ware by that method. I see you will be quite at home, Theo, in our decorating department."

"I guess you would find me a pretty poor hand at it," laughed the lad. "My fingers would be all thumbs."

"Possibly at first. It is very fussy work, I must admit. But the processes are at least easy for you to understand. Another type of decoration that will interest you is that employed when we wish to put bands of solid color around the edges of plates or dishes; also when we wish to color their entire surface. We call it ground-laying. Now how do you suppose we do that?"

Theo thought a moment.

"I can't imagine," he said at last. "Of course you could not get the color even with a brush."

"No," answered Mr. Marwood. "We must first apply to the s.p.a.ce we wish to color a peculiar kind of oil, and afterward dust over this moistened surface a finely ground metallic color."

"Which sticks only to the oiled part!" Theo exclaimed, quickly.

"You have the idea. Then the superfluous powder is blown off, and when fired the dust fuses into a solid liquid color, giving us a smoothly laid band of red, blue, green, or what you will; or perhaps a dish of solid tone if that has been the intent. We do not use this method for every type of flat color work, however, because when the powdered color blows about the workers are apt to inhale it, and it is very bad for their health. Therefore when it is possible we tint the china by hand, which can be done if the color is a delicate one and spreads smoothly; or we color the clay itself."

All this time Theo and Mr. Marwood had been pa.s.sing through the factory and going from one building to another; now they entered the decorating department.

"First I want you to see our air-brush process," Mr. Marwood said.

He led the way to an ingenious machine which by means of compressed air was spraying a fine jet of color over the surface of a porcelain plate. In some places this color rippled away into a faint tint; in others it settled into an area of a deep rich tone. By the aid of stencils the effect produced was of an exquisitely shaded ware, and Theo watched the work with delight.

"I think this air-brush process is the most interesting one I have seen," the boy cried.

"It certainly is fascinating to watch, isn't it?" agreed Mr. Marwood. "I could stand here all day; but I fear we must go on, for we still have much to see. Let us go over to where those girls are gilding. Some of them are putting a fine gold line on the china, and others are doing elaborate designs in gold. The work of the next group is to gild the handles of cups and dishes."

They pa.s.sed on and stood beside the workers.

"That does not look like gold!" exclaimed Theo, who viewed in astonishment the chocolate brown pigment that the girls were using.

Mr. Marwood laughed.

"All gold looks like that," he said, "before it is fired and burnished. In fact, all the mineral colors used to decorate gla.s.s, pottery, and porcelain look very different when they are put on from what they do after they have been subjected to the heat. That is the wonderful part of working in oxides and metallic colors. The beautiful hues we see on china or gla.s.s are the result of years of experiment. Never forget that. All china decorators have constantly to bear in mind the effect of a high temperature upon their colors. What would be attractive on the unfired clay might emerge from the kiln a very ugly product indeed. We must reckon on this fact."

Theo nodded.

"It must make the decoration of china a great problem," he said.

"It does. However, decorators have now learned pretty well what to expect. A certain carmine, for example, fires out violet. Many other shades fire lighter or darker than when applied, and allowance must be made for them. The girls who paint china become very skilful in estimating the changes in colors. These who are working beside us are doing the finest sort of porcelain decoration--faces, figures, and flowers. Those across the aisle are doing a vastly different type of work. They are putting coa.r.s.e, sketchy flowers on the cheaper ware. Some of them, you will observe, are filling in designs that have either first been printed, or transferred by the decalcomania process, and must afterward be finished by hand. The girls supply the dabs of color that are needed to complete the pattern."

"It looks easy."

"It is not highly skilled work," answered Mr. Marwood. "Some of our methods, however, are far less skilled than this one. What would you say, for instance, to decorating china with a sponge?"

"A sponge? Painting with a sponge?"

"Not exactly painting," protested Mr. Marwood. "It is not quite that. We do, nevertheless, for our cheapest ware use a fine-grained sponge cut in the shape of the desired design. This we dip in color and with it impress a pattern on the clay as we would with a rubber stamp."

"I should think you would use a rubber stamp and be done with it,"

replied Theo.

"It would not hold the color satisfactorily," explained Mr. Marwood. "But we do use the stamping method for inexpensive gold ware. We also imprint the firm name or trade-mark on the bottom of our porcelain that way before it is glazed; so we do some stamping, you see. Of course stamping is only for the cheap wares. The finest porcelain is hand-decorated--or at least the major part of it is."

Theo was silent; then he said:

"Suppose after all the work of preparing the clay, and shaping and decorating it, the piece is broken when the final glaze is put on?"

"That tragedy sometimes occurs," responded Mr. Marwood. "Often, too, a piece with many colors and much gold work on it has to be fired several times, and is therefore in jeopardy more than once. In addition to these risks you must remember the number of hands through which an article pa.s.ses from the time of its moulding to its final arrival from the glost-kiln. A delicate piece of ware is in peril every second. It may be dropped and broken; chipped in handling; its clay body may crack when exposed to the heat; the colors in the decoration may fire out unsatisfactorily; or at the very end there may be a defect in the glaze."

"Great Scott!" gasped Theo. "Why, I never should expect to get a single perfect piece of porcelain."

"On the contrary, we get a great many," smiled Mr. Marwood. "They are almost all perfect. The imperfect piece is the exception. But each piece represents untold care. We sometimes laugh at the old adage of a bull in the china-shop, but let me a.s.sure you that a poor workman can do almost as much damage in a porcelain factory."

Mr. Marwood drew out his watch.

"I believe we shall now have just about time before luncheon to go down to the kilns," he observed presently. "Should you like to?"

"Indeed I should."

"There is not much that we can see, I am afraid. However, we may be able to catch a glimpse of some of the ware being packed in the saggers."

"What is a sagger?"

"It is a large clay container in which unfired pottery or porcelain is packed while it is pa.s.sing through the firing process. These large clay vessels have come into general use as the best thing for the purpose. They stand the heat and at the same time are less liable to break or chip the goods than are containers of any other material. We make them ourselves here in the mills. In fact, there is an entire section in the clay-shop devoted to nothing but sagger making. Special machinery grinds and mixes the clay; special men fas.h.i.+on by hand the great containers; while other men do nothing but work in the wad-mills where rolls of clay to cover the top of the saggers and protect the unfired ware from smoke are made."

"Don't the clay saggers ever break?" questioned Theo.

"Sometimes, alas!" admitted Mr. Marwood. "When they do the china in them must be rescued from the kilns and put into new saggers. The old saggers are then broken up; the clay in them ground and sifted; and after being moistened again and mixed with fresh clay other saggers are modeled."

"Is the same sort of clay sagger used for the glazed as well as for the unglazed wares?"

"No. For the glazed china we generally use glost saggers that have been covered on the inner side with a coating of enamel."

All this time as they talked they had been pa.s.sing through the mill and they now entered a low hot building where a series of brick ovens with arching tops covered the floor.

"Here," said Mr. Marwood, "are the firing kilns. After the ware has been brought here in baskets it is very carefully packed in the saggers, and the saggers in turn packed in these great brick ovens.

Before they are put in the kilns have to be cooled so the heat to which the ware is subjected may increase gradually."

"But it must take forever to pack all the saggers into the kiln,"

declared Theo as he viewed in consternation the interior of one of the waiting ovens.

"It takes a long time--about five hours," answered Mr. Marwood. "Porcelain requiring a shorter firing is placed near the front of the kiln, so it can be removed if necessary before the rest is taken out. After the kiln is filled the men brick up the door of the oven and start the fire. There the china bakes from forty to sixty hours. The length of time required depends on the sort of ware being fired and the temperature of the kiln. Then the opening is unsealed and the cooling process begins."

"Do they wait until the saggers and their contents are cold before they take them out?" asked Theo.