Outstanding Glass Painting Techniques in the East Window (sII) of the Chantry Chapel of St John the Baptist, Church of St Mary the Virgin, Ewelme, Oxfordshire.

Paul San Casciani FMGP, ACR, FRSA contributes his personal views:

In Paul San Casciani’s first article last month, he analysed some highly skilled and sophisticated glazing in the insertion of heraldic charges in the shields in the traceries, and also labour-intensive abrading, all indicative of work that could only be produced by a top-level stained glass studio commissioned by such wealthy and influential clients as the Duke and Duchess of Suffolk, major players in the court of Henry VI, with their home in the magnificent manor house full of treasures nearby in the valley below the church – a building destroyed in the 17th century.

In the second of his pair of articles about this glass, Paul explores the sophisticated painting techniques employed by the artist responsible for five heraldic roundels and some other reset imagery in the same window. His expertise, accumulated during his sixty years as a traditional glass painter trained at James Powell and Son (Whitefriars) and giver of masterclasses in all the skills of ‘painting with light’ which he inaugurated in Oxford 1982 enables him to impart a unique insight into the demanding nature of the art.

For the biographies of the patrons of the glass, William de la Pole (Ist Duke of Suffolk) and his wife, Alice Chaucer, see Vidimus38.

The glass painting in the remains of this prestigious commission, even though the window is mixed with a small amount of 14th-century glass most likely from the main body of the church, and assembled by an unknown glazier between 1829–36, according to documentary sources quoted by Dr Peter Newton, still exhibits exceptional qualities that reward our attention. In spite of the various kinds of corrosion both inside and outside over the centuries and the fragmentation of subject matter giving the impression of incoherence at first glance, perseverance with this window will pay dividends.

Window sII in 2006.

Fig. 1. Window sII in 2006.

Whilst monitoring the Conservation Team at Chapel Studio, Herts, a responsibility contingent with my Condition Report, I have had the opportunity to study the window and take digital photos of the finished conservation before it is reinstated. The digital image can be enlarged greatly on the computer, provided that the photo is sharp, allowing careful and lengthy study of the most minute particulars at any time afterwards, an advance in the close study of stained glass only made available through recent technology. Lengthy on-site study through binoculars in the past did not furnish the sheer flexibility of enlargement capability digital photos now offer, with the added benefit of sitting comfortably at home at the computer screen. The great pleasure of this scrutiny is to feel that never since the medieval glass painter executed his subjects has anyone had the opportunity to look at his work in such detail, comprehend it and be at one with the past. [Fig. 1]

The aim of my detailed analyses is to show convincingly that all these roundels and other pieces were carried out by one glass painter at the top of his skills, the style perfectly in accord with the 1440s date of the Chantry Chapel complex: Chapel, Almshouses and Grammar School.

The window sII depicts various real and mythical animals often used as heraldic badges or ‘supporters’ (a heraldic term for beasts or figures who support a shield), the roundels probably complemented other heraldic displays in the church. The beasts are 1a (Unicorn, facing left, head turned to the right); 1d (Yale facing left); 2a (Yale, as 1d); 2b (White Hind trotting to the left); 2c (Lion, Sejant and cowed, facing right)); 2d (Lion, Sejant and cowed, facing left) and 5b (Hart lodged). Explanations of the heraldic terms used in this article will be found in the main text. Roundels 1a and 2b will not be discussed owing to their poor condition.


Before the artist began to paint he would have needed cartoons for tracing. Glass painters of this period probably owned collections of drawings which could be used or adapted for new commissions. The first record of artists in stained glass using paper for their drawings is recorded in an inventory of the Westminster glazing lodge in 1443, around the same time as the Ewelme glazing was underway.

Painting and staining techniques

Panel 5b

Panel 5b, Hart lodged. The inserts on the right are reconstructions using original material.

Fig. 2. Panel 5b, Hart lodged. The inserts on the right are reconstructions using original material.

The range of techniques used by the painter responsible for the roundels can best be seen in the least corroded panel of the series (5b): now located in the left cusp of the window head of light b. According to Dr Peter Newton in his Oxfordshire CVMA catalogue entry for Ewelme, it shows ‘a hart lodged’. This is a heraldic term for the depiction of a male deer (‘hart’) lying on all fours with its head erect like a sphinx (‘lodged’). Only deer are said to be lodged. Other beasts shown in a similar pose are said to be couchant. [Figs. 2 and 3]

Panel 5b, Hart lodged, detail.

Fig. 3. Panel 5b, Hart lodged, detail.

This roundel was reconstructed, maybe in the 19th century, with two fragments of another roundel from the commission, discernable as another heraldic beast, a Yale, a mythical antelope-like creature with tusks and long, curved branching horns. The left side clearly shows an antlered animal sitting on the ground. The roundel was glazed slanting down when the mass of fragments were assembled, but originally it would have looked towards the left on horizontal ground, matching the position of other heraldic beast roundels in the windows. Even though it is pitted with corrosion, its glass painting can be analysed.

The shape of the hart was traced onto a grey-green tinted clear glass with the cartoon underneath as a guide, using a tracing brush charged with pigment. ‘Pigment’ is the term traditional glass painters use for their medium, ground glass combined with iron oxide, a powder that has to be mixed to a thick paste with a liquid – in medieval times wine or urine – nowadays vinegar is used – with gum arabic added to act as a binding agent. This mixture allows the trace lines to harden and, when dry, become to a certain degree impervious to water, crucial when applying the matt to them in later stages of the painting process. Characteristic of this artist is a bold but elegant defining line showing the outline of the back, the hart’s head with its pair of grand antlers, its legs tucked underneath it, an assured trace line typical of all similar subjects remaining in this window. This subject has the key characteristics of a highly experienced glass painter: the lines, whether outlines or inner details have an immediacy and expressive vitality achieved by a sensitive pressure on the brush which results in a varying width of line appropriate at every moment to what is being depicted. The ears have light flying strokes with the brush tip contrasting with washy (i.e. with more water in the pigment) wider strokes showing the fur between the antlers. Then, dimensionality was indicated by painting groups of fine parallel lines clearly seen down the back of the long neck and along the spine; more expressive clusters of lines down the chest and under the leg.

I believe the roundel was not fired at this stage to make permanent the work done so far (which it would be as soon as reliable kilns were developed from Victorian times onwards) but executed on what is termed ‘unfired lines,’ continuing to add details without firing what had gone before, a practice requiring great skill because any mistake from then onwards could ruin everything previously carried out. The facility developed by the glass painters of earlier centuries must not be underestimated. Firing was in simple wood-burning kilns and every firing must have been calculated guesswork, so the onus was on the glass painter to carry out the entire pigment application before committing his work to the oven. The next stage was skilfully to lay a thin matt (layer) of pigment over the creature with a round-headed brush called a mop, stroke this matt with the lightest of touches with a badger brush to create a ‘silk matt’, a soft untextured film we can see all over the body and a lighter layer on the antlers. The purpose of any matt is to enable the glass painter to create form by removing some of it with various instruments to create highlights, and to control the light coming through the glass, otherwise it would glare, especially in bright sunlight. Here, evidence of modifying the matt with a hard-bristled brush known as a scrub can be seen on the lighter areas on the cheek, front of neck and flank. Finally, many tiny parallel highlighting lines going round the antlers to suggest their form have been made with the point of either the end of the brush or a sharpened stick – hence they are called ‘sticklights.’

Then the background of the subject was cleaned of any vestiges of matt overlapping the creature and a distinctive washy pigment used to create a lively backdrop of small circular florets, each with a cross-hatched centre, their background to give them definition painted on with a tracing brush – in the enlarged-to-maximum digital image the individual strokes can be seen, some darker than others where the brush had been recharged, proving they are not made by ‘picking out’ i.e. removing the matt with a stick. What wonderful facility the glass painter shows in this and all similar backdrops to his beasts, done freehand, inventively, not laboriously copied from a cartoon under the glass.

To make the glass paint permanent the roundel was fired at about 650° Celsius, fusing the pigment with its base glass and allowed to cool slowly, a vital process known as annealing, because if this is not done properly, the glass will shatter.

Once the glass was cold the final stage of the roundel began – its colouring. Working on the exterior of the reverse face of the white glass the artist painted a ‘silver stain’ (sometimes also called ‘yellow stain’) which would provide the colouring – in this case a transparent yellow – to selected areas of the roundel after it had been returned to the kiln for a second firing at a lower temperature of around 550° Celsius.

Different colour hues could be achieved by varying the strength and mixes of the stain and by the duration and temperature of the firing. Balancing and controlling these different factors required considerable expertise.

The Ewelme roundels have been stained to produce an attractive soft lemon to golden hue, confirming that the roundel was made in two firing stages. If the glass paint and the stain had been fired together at the same time the higher temperatures needed to fuse the paint to the glass would have turned the stain into darker orange and tawny hues. Variations in the colour of stains sometimes reflected the impact of particular ‘hot spots’ within the kiln. Sometimes artists used different thicknesses or mixtures of the stain on different parts of the same glass painting to achieve different effects.

The other roundels in the same series display similar techniques and characteristics confirming that they were the product of a single artist. As we will see later, some other unrelated fragments in sII are also by the same hand.

Panel 1d

Panel 1d in 2006, before conservation.

Fig. 4. Panel 1d in 2006, before conservation.

Having established this glass painter’s characteristics, it is not difficult to assess the techniques on further roundels, even though they are more strongly corroded than this one. [Figs. 4 and 5]

Panel 1d, after conservation.

Fig. 5. Panel 1d, after conservation.

The Conservation Team at Chapel Studio, Herts have removed four obtrusive mending leads, seen in Fig. 5 (please note the roundel is further obscured by a fixing bar). This roundel contains on the right a small 19th century (?) careful insertion: a fragment of another roundel from the same commission depicting part of a furry tail, probably from another Yale subject.

Sometimes written as Eale, the Yale was one of the fabulous creatures described by the Roman author and naturalist, Pliny the Elder (23–79 AD) in his best known work, Naturalis Historia. It was said to have an antelope’s body, the head of a goat, the antlers of a stag and long horns which could supposedly swivel in different directions. It was a staple of medieval books, known as Bestiaries, about fabulous animals and became adopted as a ‘supporter’ in heraldry after the 13th century. [Fig. 6]

Yale. © Museum Meermanno, MMW, 10 B 25, Folio 14r.

Fig. 6. Yale. © Museum Meermanno, MMW, 10 B 25, Folio 14r.

Yales as animal supporters occur in the arms of John of Lancaster, Duke of Bedford (1389–1435), the younger brother of Henry V, and a comrade-in-arms of William de la Pole in France. They also appear in the arms of the Beaufort family though which Henry VII traced his claim to the English throne. Peter Newton has said that the Ewelme beasts have a close resemblance to an animal supporter found in the seals of William de Pole (d. 1450) and his son, John (d. 1491).

Yales, Christ’s College, Cambridge.

Fig. 7. Yales, Christ’s College, Cambridge.

At Ewelme, the Yales are shown collared and chained. The body is decorated with silver stain yellow spots, similar to those painted on the supporters of the Beaufort arms carved above the entrance to Christ’s College, Cambridge, commemorating its refoundation by Lady Margaret Beaufort in 1505. [Fig. 7]

As with the previous roundel, the trace lines have been effected with considerable verve. The artistry of the painter is particularly obvious in the panache with which he has created the dark lines of the creature’s back, the exuberant ‘S’ of its tail and the rhythmic jagged ‘branches’ of the antlers. The hind legs are also delineated boldly and form a deliberate contrast with the watered-down pigment used round the feline paws and delicate tufts of fur: strong backbone, furry belly. Rows of thin parallel lines depict the form of the antlers and sticklights run from left to right in some cases going through the previously executed but unfired trace lines. The body shows a silk matt but the tail does not. The ground has numerous lively lines to represent the land on which the beast stands and the backdrop is again traced with circular florets with stained cross-hatched centres. The other surviving Yale roundel in light 1a, is painted in a similar fashion.

Panels 2c and 2d: Lions

Panel 2c, before conservation.

Fig. 8. Panel 2c, before conservation.

These roundels show a type of lion described heraldically as ‘sejant and cowed’; sejant means a beast seated erect and cowed means that its tail is shown between its legs. Lions were used as supporters on the seal of St Edmund de la Pole (d. 1419), the brother of William.

Panel 2d, after conservation.

Fig. 9. Panel 2d, after conservation.

When Peter Newton catalogued these roundels in situ he thought that they were ‘handed’, i.e. painted from the same cartoon in reverse positions, but under workshop conditions significant differences between the two images can be detected. For example, the lion facing right (2c) has a much larger mane and sits firmly on the ground whereas the lion facing left (2d) has its right paw raised and is three-quarter face. [Figs. 8, 9 and 10]

Panel 2d, after conservation, detail.

Fig. 10. Panel 2d, after conservation, detail.

All the glass painting characteristics of this particular painter are seen in spite of corrosion. The traced outline defines the beast strongly, in the face round the eyes, nose, mouth; back, limbs and ferocious paws complete with exaggerated claws. The painter has taken delight in the fur: enlargement on the computer reveals swirling pigment lines becoming thicker as they show the ruff, then thinner higher up the chest along with many thin lines done with the tip of the brush; likewise the tail is executed with flourishes of pigment of varying density. On the neck to our right are sticklights undeniably going through earlier painted lines, proving that what we nowadays consider the first stage of painting, tracing, was all done in one go. A particular exuberance is shown in the brush line of the many petalled florets in the backdrop, flooded with a lighter pigment to make them stand out (their execution particularly clear immediately above the lion’s head) not merely decorative but having the function of balancing the lion with its setting and controlling the light evenly across the roundel.

Panel 4b: St Mark

Panel 4b, St Mark and his emblem.

Fig. 11. Panel 4b, St Mark and his emblem.

Some other work by the same artist also survives in the same window. The best example is a full-length figure depicting St Mark seated facing three-quarters right with a lion at his feet (4b). The figure is 0.46m.h., and 0.23m.wide. [Figs. 11 and 12]

Panel 4b, detail.

Fig. 12. Panel 4b, detail.

Another superb depiction of a lion subject is found in the emblem of St Mark, the only surviving figure and originally one of four evangelists, it can be assumed. There is a head in light c done, I believe, by the same glass painter, facing three-quarters left ‘answering’ St Mark who faces three-quarters right – this is possibly what remains of St Luke – ignore the sketched-in key of St Peter as an incorrect 19th-century(?) insertion which current CVMA/ICON policy requires any Conservation Studio to keep.

Close examination reveals exactly the same glass painting characteristics as in the other beasts. The relish the painter felt for his subject is shown in the dark, loaded brushline along the back, limbs, large paws and a tail in this depiction subdued between its legs in deference to the saint who lightly touches its head, his hand unhesitatingly traced with the boldest dark line. Particularly masterly is the swing of the left back upper leg starting thin then becoming thicker as it rounds the joint, ending lightly as the painter takes the pressure off his brush. Then he uses degrees of diluted pigment to show the luxuriant flowing locks of the mane, the brush strokes varying in thickness as the ruff hangs in curls of fur. Groups of delicate brush tip parallel lines again emphasize form – along the spine, the haunch, the back hind leg. Energetic cross-hatching fills in the background between the lion’s legs and there is a tiny patch to give shadow in the ear. There is a subtle silk matt over the beast’s body and above on the folds of St Mark’s garment, which is also painted with many swinging horizontal lines and series of the finest vertical lines by the tip of the tracing brush and lightened with a scrub to create the illusion of volume. How much expertize the glass painter has invested in this one large piece of glass which then had to undergo the risk involved in two firings: one to make the painting permanent, then another at a lower temperature to render the oxide of silver a beautiful golden hue.

Panel A3, detail.

Fig. 13. Panel A3, detail.

Finally, for more glimpses into the artistry of this glass painter, it is worth examining 2 telling fragments at the top of tracery A3 which could be easily overlooked. [Fig. 13]

The piece of glass along the bottom is a tantalizing fragment of a deer nuzzling a hand. Dr Newton spotted this tiny piece of glass with binoculars, it can be supposed, and deduced it could be a scene depicting the hermit St Giles feeding his sole companion, a hind. We now recognize the glass painter’s distinctive style: a strong eloquent brush establishing all the main drawing lines – here, the animal’s head and horns, the knees tucked under suggesting the creature’s trust and devotion to its master as it lies on the ground eating from his cupped hand. Enlargement reveals the use of many fine lines denoting form and even the detail of the eye and hooves, as well as strong cross-hatching to provide shadow next to the hand and below the hind. I suggest that the fragment on the left, the still discernable subject of part of an eagle with characteristic assured tracing, although lighter than in other examples, and the finest cross-hatching on its back, is the emblem of St John the Evangelist from the missing holy figure in light d.

The identity of this expert glass painter is unknown, but I hope that this article will encourage all those interested in appreciating the art of glass painting to spend more time looking at windows that have been fragmented for it is possible to glean valuable information – and delight, from the smallest piece of glass.

The Future

Thanks to the Ewelme Trust this important glass is being secured for future generations. In addition to the cleaning and conservation work undertaken in the studio, the glass will soon be returned to the church and reinstated within an internally ventilated protective glazing system which will shield it against the ravages of the English weather and the corrosive effects of water damage caused by condensation. Don’t miss it!


Photos 2, 3, 4, 5, 8, 9, 10, 11, 12 and 13 taken at Chapel Studio, Herts. © Paul and Paula San Casciani, Stained Glass Consultants, Oxford. Images reproduced by kind permission of the Ewelme Trust, an active charity.

Further Reading

  • Newton, P. assisted by Kerr, J., The County of Oxford: A Catalogue of Medieval Stained Glass, Corpus Vitrearum Medii Aevi Great Britain, Volume 1, the British Academy for Oxford University Press, 1979, especially pp. 91–96

Goodall, J. A., God’s House at Ewelme: Life and Devotion in a Fifteenth-Century Almshouse, Ashgate Publishing, 2001

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