In 1989 restorers Jiří Třeštík and Tamara Beranová began
the investigation and restoration off figural drawings
beneath the panel paintings in the Holy Rood Chapel of
Karlštejn Castle. The detailed restorer's investigation
aimed at a compiling of all the accessible facts
concerning the drawings, their classification and consistence
with already published knowledge about the decoration
of the Holy Rood Chapel and painting during the reign
of Charles IV generally, providing thus an exact basis
for speculation on the meaning and dating of the drawings.
This aim was exceeded when the restorers, together with
Dr Hana Hlaváčková and Dr Zuzana Všetečková, discovered
three figural drawings unknown until then. These are:
one semifigure with a cross, the Holy Virgin with
Child and one Holy King.
Attention was paid to the stratigraphy of layers, to extent
and reason of a grey overpaint found on the northern
altar wall and even under the drawings proper, together
with pigments and binding media used, the relationship
of the drawings to the grey overpaint and the plaster,
and also to the grill bearing the panel paintings. The
problem of painter's signs was also considered.
The investigation was done with the help of mechanical
probes, infra-red photographs 1
and an analysis of samples taken from the drawings in
a chemical laboratory of the National Gallery in
Prague. Cross section of ground layers and drawings were
also evaluated A careful visual investigation of enlarged
photos of the drawings was also part of the work.
Results of the investigation:
The drawings rest on a coarse lime plaster without
a stucco layer, applied in horizontal stripes gradually
from above. The liniking of individual stripes is well
recognizable, they are joined aross the drawings. The
plaster is aid irregularly, the surface being quite granulated
in some places, while in others, where the mass of plaster
was stressed more, the surface is smooth (a whitish layer
near the surface of the plaster, composed of a surplus
of calcium carbonate, can be seen under the microscope
it the samples taken from these places). The plaster is
not covered by any of the two ground layers used for the
wall paintings in the Holy Rood Chapel 2.
In the course of restoration works, repairs of damaged
spots were found, done either by an older modern filler,
similar in colour to the original plaster (only more permeable),
or by a younger modern filler of grayish colour,
reaching often far beyond the limits of the defects in
the plaster layer. The coherence of these fillers was
The gray overpaint was noteced on the northern altar wall
of the chapel in three squares of the lower horizontal
line and, to a smaller extent, also in the two squares
bordering on the first ones from above. The first square
to the left of the altar, under the panel with St John
the Baptist, and the third square to the left of the altar,
under the panel with Apostle Philip, were wholly overpainted.
The second square to the left of the altar, with the drawing
of St Andrew, is covered by the overpaint approximately
to four-fifths. The drawing of St Andrew is executed in
a grater part on this overpaint and in a lesser
part directly on the plaster.
Chemical analysis showed that the grey overpaint is a mixture
of natural chalk and gypsum and is pigmented by fine carbon
black. An iodine test proved that a great amount
of starch grains is present; the material seems to be
arye starch 3.
Over the grey overpaint several sings and numbers are
written. These are: In the first square to the left of
the altar are the numbers 3 – and 4. written in white
chalk, No. 3 is carossed out with the same chalk. No.
lois written with a brush in brown colour.
Over the paint covering the third square to the left of
the altar, a painter s sign is drawn with brush
in black colour a human profile (chemical analysis
proved it to be carbon black bound by a proteineous
medium. Further, the name »Phillippus« written in Gothic
minuscule (carbon black), number 1 written in white chalk
and the number 14 written with a brush in brown colour
Over the paint covering approximately four-fifths of the
second square to the left of the altar, number 2 is written
in white chalk and N 15 by brush in brown colour. The
grey overpaint here forms the greater part of a ground
layer for the drawing of St Andrew, executed in a greater
part over this paint and in a lesser part directly
on the plaster.
In all the places where it could be verified, we found
the grey overpaint covering the figurai drawings of the
invalid lines between individual squares, whose division
was searched for, changed and given precision only in
the course of the work. e. g., in the first square to
the left of the altar, a drawing of the Holy Virgin
with Child was found under the grey overpaint, and in
the third square to the left of the altar a drawing
of a half figure with a cross. In the square
bordering from above on the squares with the drawings
of St Andrew and the Virgin Mary with Child, the grey
overpaint covered the invalid division lines of the squares.
A hypothesis based on these findings says that there is
a possibility of finding another drawing under the
overpaint, over which the drawing of St Andrew is partially
executed. The hypothesis cannot be verified because a probe
large enough to catch and uncover to (a necessary extent
the subtle linear drawing would have to be so extensive,
that it would damage the drawing of St Andrew. The grey
overpaint is impenetrable for infra- red photography.
The acquired knowledge enables us to form a judgment
on the function of the grey overpaint. The idea of the
decoration of the Chapel was specified only in the course
of the work on the drawings, the artist was looking here
for the layout of the decoration, their measurements proportions.
The grey overpaint enabled him to make corrections, to
cover the invalid division lines or drawings, whose location
or measurements were not in accordance with the final
arrangement or idea.
Further facts ensue from the results of the investigation:
The investigation showed that all drawings, with the exception
of St Andrew, run in their lower parts behind the lower
horizontal beam of the grille carrying the panel paintings.
Drawing executed directly on plaster, uncovered
2 drawing executed directly on plaster, covered by the
3 drawing executed over the grey overpaint
1/ St King,
2/ Saint with a cross,
3/ St Andrew,
4/ Holy Virgin with Child,
5/ St John the Baptist,
6/ St Peter,
7/ St Paul,
8/ Holy Bishop
distribution of the grey overpaint >>>>>>>>>>>>>>
St Andrew, drawing under the panel with St Peter detail
after restoration. Photo Kamil Wartha.
The drawings cannot be wiped off, only the base layer
of the drawing of St Andrew is less resistant to mechanical
damage. Diring a visual investigation of the enlarged
photographs, brush strokes done in black colour are very
clear in some places.
The laboratory analysis proved that the black pigment
used in the drawings and the painters sign under observation
the sign in the square with the Ho ly King, the sign of
a human profile in the square with the newly discovered
drawing of a semi figure with a cross and the
inscription »Phllippus« in the same square) is carbon
black. The analysis exvluded any presence of both lead
and silver. An analysis of the white colour proved that
it is natural chalk (fossile shells of microorganisms,
the cocolites, can be clearly seen under the microscope).
The analysis also decided that the brown colour used to
draw the Holy Bishop is composed of red and yellow ochres,
finely granulated and reminiscent of bolus 4.
Lights drawn in chalk were found also in the newly discovered
drawings. In the case of the semi figure with a cross
and the Holy Virgin, the lights were found under the grey
overpaint, only a painter's sign was drawn over it
in the square with the drawing of the semi figure with
a cross. This fact refutes a suggestion that
the lights could have been added later to the drawings
originály executed only in black colour.
All these facts support the opinion that the drawings
originated as draft drawings. In 1992 the restoration
will continue: the investigation will be finished (in
collaboration with Dr. Hlaváčková and Dr. Všetečková),
the drawing of the Virgin Mary will be uncovered and restored
and the drawing of the Holy King will be restored.
Jiří Třeštík, AHVT B 019
The Holy Chapel. Newly discovered praparatory drawing
of the semifigure with a cross, under the panel with
Philip Apostle (northern wall of the chapel, the lower
row, 3rd square left of the altar). On the left initial
removal of layer, photo IR standard; on the right – state
1 A. Krejčí of VÚZORT Institute,
Prague, executed the infra-red photographs of the newly
2 Mojmír Hamsík – Jindřich Tomek, Technické paralely
deskové a nástěnné malby 14. století. Umění XXXI
(1983), s. 308-16.
3 D. Pechová mentions in an appendix to her laboratory
report that the presence of starch grains was proved also
in the grey siliceous ground layer of the wall paintings
on the northern and southern side of a window edicule
in the Holy Rood Chapel, and also in the grey siliceous
ground of the panel paintings by Master Theodoric and
in the filling of some of the pastiglia. The plastic decoration
of the southern side of a South-East edicule contains
starch granules, too. Presumably, this is a rye starch.
4 Brown colour is used to a smaller extent
also in the drawing of St John the Baptist.