N A Dodgson and N E Wiseman
University of Cambridge Computer Laboratory, Pembroke Street, Cambridge, United Kingdom. CB2 3QG
Presented to Eurographics UK '95, Loughborough University, 28-30 March, 1995, pp.27-38.
The development of a computer based design system for ceramic tiles forms part of a Brite/EuRam project aimed at providing automated quality control for ceramic tiles. The design system is expected to provide a priori information about each tile design to the quality control inspection stations. Traditional ceramic tile design is performed on paper using a wide variety of conventional tools: pens, brushes, air brushes, etc. A completed design is separated by hand, and a silk screen produced for each colour separation. These silk screen are used to print the design on the tile biscuit, which is then baked in a kiln.
Tile design has much in common with graphic design, and hence existing computer design tools can be used for ceramic tiles. Some customisation is desirable, if only to provide an annotation mechanism for passing extra design information to the quality control system. Design for ceramics and design for paper products differ, however, in several ways, in the constraints they place on separations: (1) ceramics require much coarser half-tone screening than paper; (2) magenta and red inks are difficult to make for ceramics; (3) there are no standard inks, each manufacturer makes their own; (4) colours mix in unpredictable ways, due to the reactions in the kiln, between the chemicals used to pigment the ceramic. These constraints mean that conventional CMYK separation is of little use in ceramic tile design. It is therefore proposed that a computer design system for ceramic tiles should consists of a standard graphic design package, with suitable annotation facilities and appropriate extensions, and an automatic separation utility tailored for the needs of ceramics.
Such a computer based design system has several advantages over manual design: (1) it allows the quality control system access to the design data, incorporating annotations provided by the designed specifically for quality control; (2) it allows separations to be produced automatically, freeing the designer to spend more time designing; (3) it allows easier previewing of different colourways, and to some extent, aids in experimenting with various design elements. Weighted against this are the disadvantages that (1) the designer must learn a new tool which appears to replace rather than add to her existing repertoire of tools; (2) no computer design package is capable of achieving the wide range of effects possible with real world tools.