From clay to decoration, the union of gesture, fire and craftsmanship.
1. Preparing the Raw Materials
Hard-paste porcelain traditionally consists primarily of kaolin, feldspar, and quartz. As a general reference, a typical formulation may be given as 50% kaolin, 25% feldspar, and 25% quartz. Exact proportions vary, however, according to the manufactory, the type of piece, and the properties sought.
These raw materials are carefully prepared, ground, and mixed to obtain a homogeneous body. Depending on the manufacturing process, the mixture has a different consistency: liquid for casting, in which case it is known as “barbotine”; more plastic for jiggering; or in powder form for certain pressing processes.
Before it can be shaped, the body must have a carefully controlled composition and moisture content. The consistency of this preparation largely determines how the piece will behave during drying and firing.
2. Shaping
The body is then shaped according to the nature and complexity of the piece. Several techniques may be used: jiggering for certain turned or round forms, casting for hollow or complex pieces such as teapots, and pressing for certain series productions.
In jiggering, a mass of body is worked against a mould to obtain a regular shape. For casting, the liquid barbotine is poured into a porous mould, which gradually absorbs some of its water, allowing the material to build up against the mould walls.
Plates, cups, dishes, teapots, and other objects gradually take shape. Separate elements such as handles, knobs, grips, or feet may be made independently and then attached to the still-unfired piece.
At this stage, the piece has not yet undergone any firing: it is particularly fragile and remains entirely dependent on the quality of the shaping process.
3. Drying and Finishing
The unfired piece is extremely fragile and must be handled with care. Before its first firing, it can easily warp, crack, or develop stresses that may remain invisible to the naked eye.
It is therefore dried gradually under controlled conditions to limit internal stresses, warping, and cracking. During this stage, the water contained in the body evaporates and the piece gradually shrinks: this is known as drying shrinkage. Its extent depends in particular on the composition of the body and the manufacturing process.
Once sufficiently dry, the piece may undergo various finishing operations: removing mould seams, fettling, sanding, cleaning, and, where necessary, finishing the joins. These operations must be carried out delicately, as the piece is still highly vulnerable.
NB — Unfired porcelain forgives nothing. A shock, pressure, or stress, even one that is invisible, can leave a weakness that the fire will reveal later.
A piece that appears perfectly intact before firing may therefore develop a crack or defect after entering the kiln, when shrinkage and the physicochemical transformations of the material reveal a pre-existing weakness.
4. The First Firing — the “Dégourdi”
The first firing, known as "cuisson de dégourdi", is generally carried out at around 900–1,000°C.
This firing gradually transforms the unfired body into a solid, workable material. The body undergoes significant irreversible transformations while retaining a certain degree of porosity. This porosity is essential for the glazing stage, as it allows the biscuit to absorb some of the water contained in the glaze.
The resulting piece is known as “dégourdi” or, depending on usage, “porcelain biscuit”. It is now sufficiently strong to be handled, inspected, and glazed, but its surface remains matt and porous, very different from the smooth, translucent appearance of finished porcelain.
This first firing is also an important inspection stage: certain deformations, cracks, or imperfections become visible and may result in the piece being discarded.
5. Glazing
The “biscuit” then receives a glaze, specially formulated for porcelain. This glaze mainly contains materials capable of forming a glassy phase at high temperature, particularly feldspar and quartz, together with kaolin and, depending on the formulation, other components.
The glaze is prepared as a suspension and then applied by various methods, including dipping or spraying. The choice of method depends on the shape of the piece and the desired uniformity of the coating.
The porosity of the biscuit plays an essential role here: it allows the piece to absorb some of the water from the glaze bath and retain the glaze particles on its surface. A uniform layer must be achieved, thin enough to avoid defects yet sufficiently covering to produce an even surface after firing.
Before high-temperature firing, the glaze still has a matt, powdery appearance. It is firing that gives it its characteristic glassy, smooth, and luminous finish.
6. High-Temperature Firing — the “Grand Feu”
The glazed piece is then subjected to a second firing at a very high temperature, around 1,400°C for certain Limoges porcelains. At this temperature, the body and the glaze are simultaneously brought to the point of vitrification.
During this firing, the body of the piece becomes denser and vitrifies, while the glaze melts and transforms into a smooth, hard, impermeable glassy surface, intimately bonded to the porcelain body. The glaze nevertheless remains a distinct layer from the fired body.
This transformation gives the piece its principal qualities: whiteness, hardness, very low porosity, and translucency. The fired porcelain becomes much denser and more resistant than the biscuit, while its surface acquires the characteristic appearance of vitrified glaze.
Firing shrinkage occurs during the physicochemical transformations that take place at high temperature. The body becomes denser and vitrifies, resulting in a further reduction in the dimensions of the piece. For hard-paste Limoges porcelain, the total shrinkage between the unfired piece and the fully fired piece can reach approximately 12–14%, depending on the composition of the body and the manufacturing process.
This phenomenon must be taken into account from the design stage: models and moulds are made slightly larger than the desired final dimensions in order to allow for shrinkage during drying and firing.
NB — When wood was used to fuel the fire
Before the arrival of coal and later modern kilns, major porcelain firings were carried out in large wood-fired kilns, such as those that marked the history of the Limoges manufactories. The temperature had to be raised gradually and monitored with great precision. A firing cycle could last almost two days, sometimes 40 to 48 hours, including the temperature rise, the holding period at high temperature, and the cooling of the kiln. The kiln did not merely have to reach around 1,400°C: the fire, the circulation of the flames, and the temperature in the different parts of the kiln also had to be carefully controlled. A successful firing therefore depended as much on the expertise of the kiln operator as on the quality of the body and the work of the porcelain maker.
7. Decoration
After high-temperature firing, the piece can receive its decoration. At this stage, the whiteness and vitrified surface of the porcelain become the support for a new form of work, both technical and artistic.
Decorations may be painted by hand, applied by decalcomania — or chromolithography —, or produced using other techniques. Decoration may be entirely executed with a brush, but some pieces combine several techniques: coloured grounds, printed decoration, hand-painted highlights, coloured lines, or precious metals.
The Porcelain Painter
Painting on porcelain requires extensive training and great mastery of the hand. In Limoges, the teaching of drawing has long been connected with the development of the porcelain industry. As early as 1804–1805, a drawing school was established, notably to meet the needs of the manufactories. During the 19th century, specialised training also appeared for young women intending to work in porcelain decoration. In 1861, a school dedicated to porcelain painting was established for this purpose. The École nationale des arts décoratifs de Limoges, which became a national institution in 1881, subsequently continued this tradition of training in the applied arts.
The future decorator first learns to observe and draw: studying ornament, flowers, foliage, figures, animals, and decorative compositions. They must also learn to work on a surface that is not flat. A motif designed on paper must be adapted to the curves of a plate, the shape of a cup, or the complex volume of a teapot.
The hand must be extremely precise. The colours used are ceramic colours designed to vitrify during firing, consisting of pigments combined with fluxes. Their appearance before firing can be very different from their final colour: the decorator must therefore understand how each colour behaves in the kiln and anticipate the transformation that will occur during firing.
Depending on the technique used, the motif may be executed freehand, using a pounce pattern, or from a preparatory drawing. For repetitive production, a pounce pattern allows the design to be transferred accurately onto several pieces before the decorator applies the colours with a brush.
Brushwork nevertheless remains essential. Flowers, foliage, figures, birds, and landscapes are built up through layers of brushstrokes, shades, and lines which, after firing, will form a lasting and luminous decoration.
Chromolithography: Printed Decoration
With the development of industry in the 19th century came another possibility: reproducing a decoration in multiple copies while retaining a wealth of colour and detail.
Chromolithography was originally a colour printing process carried out through successive impressions. Each colour was printed separately and then superimposed on the others to recreate the complete image. Applied to porcelain, this principle made it possible to produce decals, commonly known in the trade as “chromos.”
The decoration is first printed on a special support using inks or ceramic colours. The printed sheet is then cut and positioned on the glazed piece. After being moistened, the decoration separates from its support and can be transferred onto the porcelain surface. The decorator must then adapt it to the curves of the piece, remove wrinkles and air bubbles, and position the motif perfectly.
This process is far from being a simple “sticker”. The curved forms of porcelain make application particularly delicate: the specifications for Porcelaine de Limoges themselves emphasise the technical skill required to adapt chromolithographic designs to the wide variety of shapes and curves found in porcelain pieces.
After application, a firing fixes the colours permanently to the glaze. Depending on the desired result, the decoration may then be enhanced or completed by hand by a porcelain painter.
Chromolithography thus makes it possible to reproduce the same decoration faithfully across large series, while hand painting retains its essential role for artistic pieces, details, retouching, and the most refined creations.
In Limoges, these two approaches are therefore not necessarily opposed: decoration can combine the efficiency of printing with the precision and sensitivity of the human hand. It is this combination of industrial processes and traditional craftsmanship that enables manufactories to produce both large series and exceptional pieces.
8. Firing the Colours — the “Petit Feu”
Colours applied to the glaze generally require firing at a temperature considerably lower than that of the high-temperature firing. Depending on the nature of the pigments and decorations, this firing may take place at approximately 700–900°C.
This firing, traditionally known as “petit feu”, allows the components of the decoration to fuse to the surface of the glaze without exposing the piece once again to the very high temperatures of the high-temperature firing.
Mastering this firing is essential: a temperature that is too high or an unsuitable firing cycle can alter the colours, change their appearance, or damage the decoration. Since different colours do not always mature at the same temperature, several firings may be necessary to complete a complex decoration.
Each passage through the kiln therefore represents another stage of risk and quality control for both the decorator and the porcelain maker.
9. Applying Gold and Platinum
Precious finishes are generally applied after the other decorations. Gold, platinum, and other precious metals may be applied with a brush to create lines, borders, highlights, or specific decorative motifs.
The fileur is the craftsperson specialising in applying lines and borders to porcelain pieces. Using a very fine brush and a steady hand, they apply a line of gold, platinum, or colour along the edge of a plate, cup, dish, or other piece.
This work requires great precision: the brush must remain perfectly steady and even while the piece is rotated. The fineness and continuity of the line depend as much on the mastery of the hand as on the regularity of the piece's rotation.
The fileur may also create multiple lines, borders, outlines, or highlights, sometimes in combination with other decorative techniques.
This stage requires patience, a steady hand, and experience. On a richly decorated piece, a variation of just a few millimetres can be enough to disrupt the harmony of the decoration.
10. Precious Finishes
Gold and platinum are applied after the other decorations, in the form of preparations containing genuine precious metals. They can be used to create lines, borders, highlights, solid areas, or raised decoration. The fileur plays an important role in drawing the lines that emphasise the shape of the piece with perfect regularity.
These decorations are fixed by firing at a lower temperature than the high-temperature firing, generally around 750–850°C, depending on the nature of the product used. Several firings may be necessary when the decoration combines different techniques.
Incrustation
Among the most refined techniques is incrustation, which makes it possible to create a decoration engraved into the glaze. The motif is first transferred onto the piece, and the areas that are to remain untouched are protected with a varnish traditionally known as bitumen of Judea.
The piece is then immersed in a hydrofluoric acid bath. The acid attacks the unprotected glaze and thus etches the motif. After rinsing and cleaning, the engraved areas receive two successive layers of gold or platinum, with intermediate firings.
The finish can then be achieved by agate burnishing: a perfectly smooth and very hard piece of agate is used to polish the precious metal and give it its characteristic lustre. The contrast between glossy and matt surfaces brings out the relief of the decoration.
Other techniques, such as raised gold, make it possible instead to apply a raised metallic decoration using a special paste, which is then fired and finished with fine gold.
These particularly delicate finishes may require numerous operations and several passages through the kiln. They rank among the most refined skills involved in the decoration of Limoges porcelain.
The ten stages presented here are only a summary of a much more complex process. From the preparation and inspection of raw materials to shaping, finishing, firing, glazing, decoration, quality control, and retouching, the manufacture of a single piece may require numerous operations and the intervention of several specialised craftspeople.
Modeller, mould maker, jigger, couleur (slip caster), assembler, repairer, decorator, fileur, gilder… Each intervenes at a precise stage of the process and contributes, through a highly specialised gesture, to the creation of the piece.
From raw material to the final brushstroke, every stage requires precision, patience, and savoir-faire. Several passages through the kiln, sometimes separated by successive operations, are necessary before the piece reaches its final form. This succession of gestures and specialised crafts contributes to the quality, durability, and renown of Limoges porcelain.