17 six blue-painters and two apprentices amongst the 29 painters employed overall at Meissen. Johann Gregorius Höroldt got to the bottom of what was causing the shortcomings in underglaze blue ware – incorrect formulation of the paste – by constantly experimenting with the composition of the cobalt blue colour, with fluxing agents, glazes and other pastes and with firing temperatures and the kiln atmosphere.18 By 1737, a total of 259,620 porcelains in the white were already matched by 178,351 in blue. Only when the recipe further improved in 1739 was there a significant drop in complaints concerning ware decorated in underglaze blue. Indeed, experiments with varying blends of paint, pastes and glazes are still carried out today with a view to further enhancing the quality of the decorative detail. Blue-and-white porcelains, and notably Blue Onion Pattern wares, are, and always have been, produced using cobalt blue. Varying intensities of colour are accordingly brought about with the aid of a single colour. Along with the chromium-oxide green used, for instance, in the “Vineleaf” pattern, cobalt blue is the only colour that does not scorch when glost-fired at around 1,400 degrees Centigrade. A basic distinction is made between two types of painting: overglaze and underglaze decoration. Overglaze decoration is applied to porcelain that has been glazed in the white and undergone two firings. It is applied to the glazed surface and subsequently baked at around 900 degrees Centigrade in a process known as enamel firing. Underglaze decoration is applied to the bisque-fired, still porous porcelain after this has undergone initial firing at around 950 degrees Centigrade, after which it is paintable, absorbent and non-water-soluble. It is necessary with both variants to produce an outline drawing of what is to be painted, either free-hand or with the aid of a template. The Blue Onion Pattern is a “fixed” design, i.e. the layout of the various decorative devices is determined by the object involved. This is why painters use perforated templates made of metal foil (fig. 2) into which the pattern’s outlines have been punched by hand as a means of defining the areas to be painted. First the template is placed on the item in question and then charcoal dust is dabbed over it with a small rag, leaving the outlines of the pattern visible on the area to be painted. The blackish cobalt oxide is now combined with a painting medium in preparation for its being applied to the once-fired, still porous porcelain with a variety of brushes. Painters need a sure and steady hand for this, since the paint is immediately absorbed by the porous ceramic body and any mistakes made cannot be rectified. The painted detail is varied with the aid of lines as well as by rendering outlines and
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