Ceramic designs on humidity
Humidification plays an essential part in the design process for Royal Doulton, one of the world’s leading manufacturers and suppliers of porcelain and fine bone china.
Over 400,000 pieces of decorated tableware leave the factory gates at Royal
Doulton each week. Humidification plays an important role in the process that
sees each piece bearing an exact replica of the artist’s original design.
Royal Doulton is more than a household name, it’s also one of the world’s leading manufacturers of fine china and bone china. The company has a diverse customer base, its table and giftware isn’t just used in homes but hotel chains, embassies, by airlines and commercial catering and banqueting specialists across the globe.
Brands include Royal Crown Derby, Minton, Royal Albert, Caithness Glass, Holland Studio Craft and Royal Doulton itself. A major element of the business is the collectible ranges which include hand decorated figures, character jugs and nurseryware.
Royal Doulton is based in Stoke-on-Trent. It has four ceramic factories in the immediate region, one in Derby and another in Indonesia. There are also crystal and glass factories in the West Midlands and Scotland. Royal Doulton has invested heavily in modern flowline production systems, computer controlled energy saving kilns and automatic glazing lines, making the company’s factories among the most modern and efficient in the industry.
Vapac humidifiers are an important part of the manufacturing process and come into their own in the decorating process. There are many ways to decorate tableware, Royal Doulton uses lithographs. Some patterns on collectible ranges are produced using a direct printing method.
For everyday ware, the artist’s original designs are photographically
transferred onto a sheet of fine paper. This acts as the carrier for the design
and is coated with a thin film of plastic. Each lithograph sheet can then be
stored until needed.
To apply the design to the china the lithograph sheet is soaked briefly in soapy water to loosen the transfer from the paper and is then carefully slid onto the china. Once in place the lithographer smoothes the design into the correct position and by using a hand held sponge removes any air from under the transfer.
Temperature and humidity control at this stage is vital, so it is maintained at 21°C plus or minus 5°C with 60% relative humidity plus or minus 2%. “Lack of humidity would result in the paper that is used to carry the design drying out too quickly, causing the edges to curl which could affect the printing process” says Dennis Preston, Works Engineer at Royal Doulton’s Baddeley Green site.
Two Vapac units incorporating their own operating system are being used. In line with Royal Doulton’s approach to energy efficiency, the Vapac unit is designed to minimise wastage of water and energy whilst ensuring a full and fast response.
Water around the Stoke area is soft, but even soft water contains trace elements
which can have a profound effect when boiled. The Vapac range has been designed
to cope by automatically adapting to changing water conditions within the cylinder.
Once decorated, the china goes off to the kiln for firing at 900°C. When cooled, the patterns are permanently fixed in the glaze. Some figures and tableware designs can be fired up to four times at the decorating stage, allowing artists to build up the colours and decoration needed to complete the design.
The products end up on the shelves of numerous retail outlets. Annual sales are around £200 million, half of which are overseas in 80 countries.