The Invention of 18th Century Ceramic Transfer Printing
The invention of transfer printing on porcelain and pottery in the C18th was a significant development in the ceramic industry.
Robert Hancock was a superb copper plate engraver at the London Battersea enamel works, which was producing small luxury items such as snuff boxes and scent bottles designed to imitate silver. Hancock brought his knowledge and skills to the Worcester works in 1756, following the Battersea closure. Dr John Wall, the owner, took readily to Hancock's proposal to apply the same principle of transferring decorations to the little copper boxes, for which Battersea was synonymous, for decorating the porcelains. Hand painting the wares was laborious and thus expensive and Wall took little persuading to agree to experiment with the idea. Hancock's printing skills produced the first copper plate for the famous black printed King of Prussia transfer print in 1757.
These first printed decorations, at Worcester and at the Sadler & Green works inLiverpool, were black onglaze, and limited in size by practicality and the smaller available paper size manufactured. Once the transfer had been applied, using fine tissue or even very fine fabric, and dried, a fine coating of glaze was added and the piece fired in the glost kiln sufficient to harden on the glaze.
Josiah Spode took the basic principle and developed underglaze blue transfer printing, the development of paper roll manufacturing enabling production of larger sheets of paper. These transfers were pulled from copper plates which were line engraved, a highly skilled and lengthy process.
By the turn of the century, underglaze transfer printing had reached such a level of perfection that the finest engraved work on the copper plate could be perfectly reproduced onto the ceramic, producing top quality wares of top quality. It seems all the more strange, perhaps, that a variation on this successful paper transfer decoration employs a method which, on cursory examination, seems to revert back to the limitations of the early period.
The earliest transfer printing process, both on and under the glaze, began with a line engraving, as did the plates for Bat printing. But very quickly, the engravers began to use a fine stipple punching to exploit the different properties of the bat method; the whole design was made up of tiny dots, the engraver varying the size and spacing, controlling the depths of tone in the resultant print - sometime using thousands of tiny individual dots.
Spode Can Bat Printed c. 1810 in Soft Black with Botanical Pattern
Before the decoration could be transferred, instead of dampened fine tissue, a glue bat was prepared: animal glue, produced from boiling up bones and skins, to which was added ale and ising glass, was then poured into shallow pans and allowed to set to a thin jelly sheet, about one eighth of an inch thick. This sheet, or bat, had a smooth shiny surface ideally suited to hold the tiny amount of oil used in the transfer process.
Due to its organic nature, the glue bat could be affected by humidity and very damp conditions caused the bat to reabsorb the water driven off in boiling, rendering it too tacky or too fluid. Bats could be wiped clean after use and stored face to face covered with a damp plate, and be used again for two or three days. After this time, they would become too hard and lose the very slight tackiness required for the transfer. Bats which had suffered from adverse weather or were past their best condition, could be recycled by reboiling. It was part of the print shop routine that fresh glue or old bats were reboiled and poured into the pans, to be set ready for the following day.
The prepared plate was lightly oiled, the surface being wiped to leave oil only in the indentations of the design. The bat was pressed firmly against the plate and lifted to leave the design in oil on the glue surface. The bat was then applied to the glazed ceramic, pressed down and carefully lifted away, the design in oil transferred now to the surface of the glaze. The nature of the glue bat was well suited to hold the oil and transfer it without smudging - although careless or too hasty lifting could result in the oil being taken back and away from the ceramic and the result can occasionally be observed, where the removed transfer resembles a wipe-out mark across the finished print.
The bats were pliable and ideal (with some limitations) for application to curved surfaces such as jugs, cups and bowls. However, this same quality also presented problems, since the flexibility was accompanied by elasticity, resulting in some distortion to the print as the bat was applied to the surface - not noticeable in small designs or on flat surfaces, but a larger design applied to a bowl, for instance, could produced some uncomfortable results, with oddly stooped figures, or bent pillars.
The distortion can be a helpful guide for identifying if a print was transferred by paper or bat. Changes of plane, for example in a moulding, were also problematic in bat transfer - overcome frequently by the simple expedient of cutting off the design, often with an oddly abrupt result, or by applying gilding to disguise the problem section. Differences may also be observed in prints from the same plate, the stretch in the bat naturally being inconstant from transfer to transfer.
Bat transfer printing was used on pottery and the porcelains but it was particularly effective in creating elegant designs on the new bone china - the fine porcelain body proved especially well-matched to the restrained results capable of being achieved using the bat method. Several factories made use of this quality, which is epitomized nowhere better than in the Spode wares from 1810 to 1830 (some bat printed wares continued after this date but it had largely passed it heyday before the middle of the century).
There is some recently discovered evidence that the 18thC factories employed some bat printing but it is to date inconclusive. Sadler makes mention of glue bat recipes and it is certainly possible some of their printed wares used this method in some form. Similarly, we do know now that Wedgwood, having spoken scathingly of the method, appears to have changed his opinion and made use of it for applying armorials to the pottery's commissioned wares: in conjunction with the hand painting of extensive services, the armorial could be economically inserted into specially reserved cartouches or areas otherwise incorporated into the design on each piece in the service. A commissioned service could be extensive and expensive, perhaps comprising upwards of 500 pieces and the small contribution played by the labour saving bat additions can easily be appreciated.
In transfer printing with paper, the copper plate was warmed and primed with thicker oils mixed with powdered enamels, heated pressed, before the coloured transfer was applied to the surface of the ceramic. No heat was required for priming the plate with the finer oil which did not need to carry the colour, enabling very fine engraving to be transferred and reproduced onto the surface. Once the oil design was transferred to the glazed surface of the pot, finely ground enamels mixed with a little finely powdered glaze, and flux to lower the melting point, was pounced or blown on before the pot was placed in the enamel kiln at a low temperature, just sufficient to melt the glaze and enamel, and fuse the design to the underlying glazed surface. However, the bat print being essentially onglaze, (unlike the underglaze blue printed paper transfer), would always be more vulnerable to damage and wear.
The makers quickly recognized the opportunities now offered for fine, subtle designs, perfectly suited for delicate rendering of landscape, introducing light and shade, subtleties of tone.
For all its subtleties and the beautiful effects which could now be achieved, bat printing proved time consuming and required great skill, both for the engraving of the original plate and in the application of the bat to the ceramic. The paper transferrer had at least the benefit of seeing the hint of coloured design through the tissue, assisting correct placement, but the bat transferrer was working 'blind', both by nature of the bat and the fact only a fine oil was being transferred. Placement relied on skill and experience, a keen eye and a steady hand. Therefore bat printing was by no means the poor relation in ceramic decoration and most factories quickly abandoned the process, so that it largely died out by 1830. Within its period, the charcoal grey/black was the most popular but other colours were introduced, including blue, pink-orange and purple, often with added hand painted enamel banding or enhanced and warmed with gilding. The latter added to the cost but, judging by the quantities produced, was obviously in demand by customers who appreciated the stylish and elegant results for their tea and dinner services.