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BCD Special Report on
Historic Churches
18th annual edition
37
crown of thorns dripping down his forehead
and face, between two men in profile. They
are deliberate caricatures of ugliness, with
bulbous noses and exaggerated expressions
of hatred, and they are shown spitting at
Christ, drops of spittle falling from his face.
To the east of this scene were fragments of
a figure seated on a throne with the right hand
raised in blessing. An inscription below the
panel is thought to read ‘… Sancta Trinitas…’
and the scene is therefore taken to depict
God the Father seated on his throne, with the
crucified figure of Christ between his knees and
the dove above representing the Holy Spirit.
Opposite this, on the south wall of
the nave, was the Image of Pity. A popular
devotional image of the early 16th-century, it
shows Christ, seated on a stone-built tomb,
and dressed only in a loin-cloth displaying
the wounds of the Crucifixion, surrounded
by the Instruments of the Passion.
At the east end of the south aisle was a
painting of Christ before the crucifixion with
the words Ecce Homo (‘Behold the Man’). Christ
is depicted seated, wearing the crown of thorns.
To the left of him are a ladder and a spear, two
more of the Instruments of the Passion. His
wrists, knees and ankles are bound with rope
and near his feet is a large skull, a reminder
that the crucifixion took place at Golgotha, ‘the
place of the skull’. The other paintings from this
late medieval sequence were saints and angels,
architectural decoration and linking borders.
A massive St Christopher was placed in
his traditional location immediately opposite
the main doorway, although all that survived
of the original painting was the haloed head
of a child on the shoulder of the much larger
figure of the saint. To the left was a church,
with a robed figure carrying a rosary: the
hermit who charged Christopher with the
task of carrying travellers across the river.
Within several of the window splays,
paintings of angels and saints were found:
St Roche, St Margaret of Antioch (spearing a
dragon beneath her feet) and angels carrying
a shield with symbols of the Passion.
The original wall paintings at St Teilo’s
church were executed a secco (painting onto
a dry plaster or limewash layer) as opposed
to a fresco, where the painting is executed
onto a fresh or wet plaster. With buon fresco
(literally ‘true fresco’), paintings are executed
using powder pigments ground and mixed
to a paste with water. They become bound
with the wall surface through the carbonation
of the lime in the lime plaster. Lime putty
(calcium hydroxide) sets through a process of
carbonation with the water element evaporating
off and atmospheric carbon dioxide being
absorbed into the plaster to form calcium
carbonate. As this process occurs, minute
quantities of lime pass into the pigment layer
and carbonate, thereby binding the pigments.
Replication
The reconstruction of St Teilo’s wall paintings
was carried out in a number of stages. A series
of colour-matching tests was carried out and
a simple palette of colours determined so that
batches of colour could be made-up for use.
The wall paintings had originally been
executed onto a thick limewash ground and
in such cases the pigments normally require
an additional binding medium. However,
where thick, freshly applied limewashes are
present, it is arguable that the carbonation of
the calcium hydroxide, which makes up the
main component of this layer, would impart an
element of ‘fresco’ binding to the pigments. Such
effects are sometimes referred to as fresco-secco
,
a somewhat confusing and contradictory term.
The new wall paintings at St Teilo’s have
been executed using traditional secco painting
techniques, in this case using a casein binder.
Casein is the principal protein in milk and has
been used since Egyptian times to make a form
of paint known as tempera. Casein is produced
commercially by the addition of acid, which
produces casein powder. This is mixed with
water and ammonia, in the form of ammonium
carbonate, to produce ammonium caseinate,
an adhesive casein binding material that can
be diluted and mixed with traditional powder
pigments. These are ground together to form a
paste, which can then be applied in thin glazes.
Several applications may be necessary to build
up the colour, but the matt finish produced by
this method is ideal for large mural subjects.
During the Medieval and Renaissance
periods, wall paintings in Britain were, for the
most part, executed using a very basic palette
of readily available and relatively inexpensive
earth pigments: red and yellow ochres, lime
white and carbon black. While the range of
colours available to the artist included pigments
such as red lead, white lead, vermilion, green
earth, malachite, azurite and lapis lazuli (natural
ultramarine), these pigments were often too
expensive for the average rural community, and
so their use tended to be limited to the finest
and grandest schemes, such as those which
survive in a number of cathedrals and palaces.
Most of the powder pigments used at
St Teilo’s were sourced from Clearwell Caves
in the Forest of Dean, Gloucestershire. The
Clearwell Caves are among the earliest, as
well as one of the last surviving, producers of
natural earth pigment (ochre) in the British
Isles. Ochre is thought to have been mined here
since the Middle Stone Age, more than 7,000
years ago, and the Forest of Dean mines were
once famous for good quality, rich pigments,
particularly shades of red and purple. Purple
ochre is an unusual natural earth pigment;
similar colours are usually only available in
synthetic forms. For the project at St Teilo’s,
some of the Clearwell pigments were mixed
with other natural pigments obtained from
L Cornelissen & Son, established in London
as an artists’ colourman in 1855, in order to
obtain close colour matches to the pigments
found in the original wall paintings.
To set out the scheme, first life-size
photographic prints of the surviving wall
paintings were located in their original positions
on the walls of the reconstructed church.
Left: Original wall painting showing The Mocking of Christ, c1530 (Photo: St Fagans National History Museum) Right: The pounced cartoon for the reconstruction of
The Mocking of Christ: the main outlines of the design (the ‘cartoon’) are pricked through (or ‘pounced’) using a needle or small spiked wheel to create a line of holes
and a small cloth bag containing fine powder pigment is patted over it to transfer dots of pigment, and thereby the image, through the holes
Tools of the trade: red iron oxide powder pigment, a
pin wheel for incising the design through the cartoon
and a pouncing bag filled with pigment