For several years before the opening of the biggest exhibition so far of the works of Petr Brandl, his contemporaries and successors (1968) I worked on systematic research of his technique. At the same time I compared it with pictures by Karel Skřeta and other painters who worked in Bohemia, also paying attention to the relationship with previous development. Today, after a study of the techniques of the transition period, especially the changes in the technique of epitaphs still painted on wood, this development can be seen in new contexts. I shall return to this in greater detail in the next number.

Some time in the seventies of the 16th century a new line of development was formed (changing the tradition till that time of white priming), influenced by the cultural contacts between the Habsburg court and the Catholic nobles and southern countries, particularly Spain. These contacts reached their peak under the Emper or Rudolph II (1552-1612). The grounds f or painting on canvas and on wood were dark, grey or brown, the colours used being unburnt ochres with an admixture of black. If they were red, they had the cold violet tone of Venetian red with an admixture of black. The new style penetrated relatively quickly, as I confirmed during the repair of 14 of Theodoricus's pictures in the Chapel of the Holy Rood in Karlštejn Castle, and also during the repair of the two-sided painted panels by the Master of Třeboň at Církvice. The same kind of old luting is to be found in the pictures from the16th century owned by Prague Castle. I ascertained that these period cementings correspond perfectly to the contemporary grounds for painting.

Petr Brandl links organically onto the technique of advanced baroque painting, which Karel Skřeta worked with after 1640 when he returned from a study tour in Italy; this Venetian method came to be used constantly in Bohemia around the middle of the 17th century. A characteristic feature of pictures from this time is a single-layer ground, the main components of which are burnt ochres with a small quantity of pigment mixed in. They are the colour of burnt bricks of a lighter or darker tone, sometimes almost orange-red. In most cases they are single-layer, in Venice there were often more layers in these coats. They differ from the grounds of the Rudolphine period pictures in their warm tone, and they are lighter. The brick-red grounds are the foundational optical condition for chiaroscuro painting, in most cases done by the layer method. Then in surfaces of carnation the warm red ground gives a very beautiful resulting tone, reminiscent of the brittleness and transparency of porcelain. Over the whole area this basic tone helps to consolidate the colour composition and gives the painting unity. Brandl´s technique has the following characteristic features: The canvas has a medium thick cloth weave, usually 10 threads to 1 cm; coarse canvas with 7 threads to i cm ivas occasionally used, more often canvas with 12 threads to 1 cm. The fibre is flax – the fibres were tested, in the case of all the pictures by Petr Brandl and Karel Skřeta, owned by the National Gallery in Prague and only in one picture was hemp found.

The ground is thick, the colour of burnt ferric earths with an orange shade, fairly light. The earth used as similar to the kind quarried near Srbsko in the Beroun region. Research of the basic layers, carried out by Dr. J. Tomek in the National Gallery's laboratories, using spectral analysis and X-ray difractology, confirmed that the main component of the ground is siliceous earth coloured with ferro-compound. Under a microscope very rough grains of vermilion can often be seen in the ground, also ochre and crystalline, cooper green. It contained larger or smaller amounts of oil. According to long-term reactions to climatic changes and variations of dampness in the air it is evident that the priming was rather over-glued and too thick. After a time sharp crackles formed in it, around which the paint rose in bowls and was apt to f all off. W. L. Reiner's priming has different qualities – it is also thick, but too bound with slow-drying oil.

Petr Brandl – The »Lobkovic«, Self-portrait around 1697, detail, X-ray photograph.

Research of the pictures showed only single layer priming by brandi. In those cases when a cross-section of the painting revealed more layers it was clear from comparing samples that the layers directly on the ground were part of the underpainting. only in two cases, when the painting was done on other supports than canvas, a thin, very light ground was used? The drawing. So far as it was possible to take samples with the drawing, it was clear that this was always done with a semitransparent brownish-black tone, usually composed of sienna and black. The underpainting and painting. During research work on his pictures it became clear that Petr Brandl devoted great care to build-up his paintings. After the preliminary sketch with the brush came the underpainting of the picture. At this stage the composition and modelling of the shapes were already settled, and such based for the final colour of the picture. It cannot be said that the preparation of the picture with the underpainting was just a craftsman's custom, a method of work passively taken over from a teacher. Even in the underpainting great efforts were evidently made to attain the artistic effect. Besides under paintings with cold or warm grey, we often find in the terrain, in the draperies or in the background of portraits, some white underpainting, a mixture of white with a slight quantity of pigment. In the paint f alls off where there is this white underpainting, it may lead to the idea that the picture had a white ground. But so f ar it has been found in all cases that this white layer is part of the painting, a purposeful preparation for layer painting. This method of building up pictures is used even in Brandls early works, and a similar one is to be found in the pictures of Karel Skřeta, where we find warm grey underpainting, in the thick coats and semi-glares, dark grey, covering pinkish or white. As has already been said, only at the time when Petr Brandl was influenced by Halbax did he relinquish layer painting in some pictures, and the careful preparation that proved itself so well that, even after centuries, even the cold transition tones and those on dark brick-red, grounds have retained their freshness. It may be said that the great majority of Brandl's pictures are constructed on the layer technique, which he did not give up completely even at the time when he was most influenced by Halbax.

  author
Věra Frömlová, AHVT A 017 (N. H.)

A) The Healing of blind Tobias — deep shade of flesh-colour
8 lglaze with grains of vermilion and black
7 light grey glaze – grains of black, vermilion and natural sienna 0,010-0,020 mm
6 ochre layer with excess of binding agent contains
ochres, black, grains of vermilion and malachite 0,015 mm
5 middle grey layer 0,015 mm
4 flesh tone of gold colour – unburnt ochres, lead white, minium, negligible black 0,015-0,25 mm
3 light flesh tone – lead white, natural ochres, touch of minium and black 0,028-0,046 mm
2 brown underpainting – natural ochres and negligible black malachite and 0,020 mm
1 fragment ground of clear red colour, also contains gold ochre, grains of vermilion, glaze red, occasionally lead white

B) Petr Brandl, The Vision of St Theresa, Church of St Joseph, Prague – Lesser Town, 1697; sample taken from half-shade
7 of flesh colour
6 glaze with excess of binding agent, contains natural sienna and touch of black
5 pinkish layer of flesh tone is of irregular thickness, contains larger amount of binding agent 0,025-0,030 mm
4 light-grey layer — white, ochres, a touch of black, malachite and glaze red 0,030-0,048 mm
3 fragment of grey-green paint layer with grains of malachite
2 grey – brown underpainting (drawing ?) – contains burnt ochres, grains of black and sienna 0,013-0,030 mm
1 clear red ground of burnt ochres, 105 mm

C) Petr Brandl, Jacob Receives Joseph's Bloodstained Coat – half shade of carnation
3 glaze – natural sienna and black 0,008 mm
2 brown layer – grains of black, burnt ochres, red lake, malachite 0,029-0,043 mm
1 clear red ground composed of burnt ochres, grains of vermilion, malachite and occasionally also of lead white and black

D) Michael Václav Halbax, (St Paul in Prison – shade of carnation)
4 two glaze layers, contain grains of black and malachite 0,008-0,028 mm
3 brown with black 0,058 mm
2 middle brown with grains of vermilion, red lake, black, malachite, rich on ochres 0,029-0.043 mm
1 clear red ground of silicates and burnt ochres, cont. single grains of vermilion, malachite, black and lead white 0,217 mm