Project Development

Recording and archiving stained glass

Many places of worship house magnificent treasures of art that are seen by only a few.  People can be put off the nature of the building, or in quite a number of cases, there is simply no public access.  When able to see such artwork, the lighting of the windows will not always be optimal for satisfactory viewing.  Thus stunning windows go largely unnoticed and this art form is rarely appreciated.  I have been trying to make such artwork more readily available to the public by photographing the windows, but the photography of stained glass windows is beset with difficulties:

  • Light levels within and outside the building are rarely, if ever favourable, with insufficient direct light, or constant partial shadow.
  • The height and size of the windows typically results in perspective distortion when photographing with standard lenses.
  • Stained glass windows present a dynamic range, beyond the capabilities of the best cameras: is exposure bracketing then painstaking reassembly of the window the best solution?
  • The removal of the strengthening bars requires demanding image editing with manual interpolation of the four or five ‘missing’ 1cm strips of window.  Are there better techniques for such work?
  • With the image complete, how best to present a reproduction of a window that might be 4-6m tall and backlit by natural light?

I am inclined to think that removing the main subject of a windows from its context will make it more readily appreciated by the viewer (removing dedications and decorations) – certainly this will provide a more manageable aspect ratio.  However, this does then preclude the image from being quite so useful as a historical reference or for insurance archive purposes.  Thus it would seem wasteful not to archive the entirety of a window and then crop out the ‘flesh’ for more public consumption.  This does raise an important consideration: what is the current thinking on most effective archiving of data files when the images are required as an insurance backup against catastrophic damage?

Exposure bracketing was used to produce six images of the stained glass window, to provide a full range of exposures from heavily underexposed (to reveal detail in the darker areas) through to heavily overexposed (revealing detail in the lighter areas).  From those six images, a seventh image was constructed, single segment of glass at a time, having first selected the most appropriate piece from the original images.  Considerable time was then spent remove the unsightly, horizontal metal support bars before some cosmetic ‘cleaning’ of the seventh image.  The three images below illustrate the process.

Project Development

British Society of Master Glass Painters

It would be hugely wasteful of a project based upon stained glass for me to overlook the wider benefits of such work.  The formal archiving of stained glass windows for historical/artistic reference or for insurance purposes seems an eminently sensible facet of my planned work.  With this in mind, I have contacted the British Society of Master Glass Painters, seeking their professional opinion on what they would most want to see from an archive image (or series of images).

newbsmgpheaderFounded in 1921, the BSMGP is Britain’s only organization devoted exclusively to the art and craft of stained glass.  Its chief objectives have been to promote and encourage high standards in the art and craft of stained glass painting and staining, to act as a locus for the exchange of information and ideas within the stained glass craft and to preserve the invaluable stained glass heritage of Britain.

I await a response to my enquiry…

Project Development


raw-file-format-symbolWhen first I dipped my toes into the waters of stained glass window photography, through habit, I captured the images in JPEG format which is inherent with problems that work in antagonism with image quality.  At its most basic level, JPEG is a ‘lossy’ format – every time a file is saved, image quality is sacrificed. By contrast, RAW can be lossless.

More significantly, the improved handling of Dynamic Range makes capture in RAW format eminently more sensible for stained glass windows, which are notorious for having a very high dynamic range.  RAW allows the post production flexibility to darken (burn) the highlights while raising (dodging) the shadows. It is possible to tone-map an image appropriately in a process far more akin to analogue work in a darkroom.

Shooting in RAW raises an exciting prospect for this project: might it be possible to achieve the same results with a single RAW file that previously required a series of six exposure bracketed JPEG files?  If not, I suspect there could be a reduction in the number of exposure bracketed RAW files compared with JPEG files.

RAW key advantages for this project:

Increased dynamic range:  RAW files contain a greater dynamic range – the ratio between the maximum and minimum measurable light intensities (white and black, respectively).

Increased Colour Depth:  JPEG is captured in 8-bit, RAW can be captured in 12-bit or 14-bit

  • 8-bit means 28 tonal values (256) for each colour (red, green, and blue) per pixel (16,777,216 unique colours)
  • 12-bit means 212 tonal values (4,096) for each colour (red, green, and blue) per pixel (68,719,476,736 unique colours)
  • 14-bit means 214 tonal values (16,384) for each colour (red, green, and blue) per pixel (4,398,046,511,104 unique colours)

What can the human eye see?  It is worth highlighting the fact that the human eye is unlikely to be able to discern all the colours in an 8-bit image, so shooting at 14-bit may seem nonsensical. When discussing the number of colours perceptible to the human eye, wisdom tends to refer to the 2.4 million colours of the CIE 1931 XYZ colour space.  This is based upon sound scientific evidence, but might be rather limited by context.  When referring to both chromaticity and luminosity it may be possible for the human eye to be sensitive to 10-100 million distinct colours.

Raw files are the equivalent of negatives:  A RAW file is the image data exactly as captured on the sensor. Any settings you apply in white balance, Picture Styles and some other areas are only appended to the image as a small header file. This means they can be changed later in RAW conversion software such as Canon’s Digital Photo Professional.  The RAW file is an original record of what was ‘seen’ by the camera.

RAW format disadvantages:  Pleasingly, none of the main disadvantages in using the RAW format are a concern in the photography of stained glass:

  • RAW file require post-processing
  • File sizes are considerably larger
  • Fills up the buffer more quickly (however, the EOS-1D X Mark II achieves a maximum burst rate of up to 170 full-size RAW files)
  • It is a propriety format (Canon RAW files are .CR2, Nikon RAW files are .NEF)


Project Development

Henry Holiday

The stained glass windows I have most closely studied lie within the Chapel of St. Nicholas, which houses a magnificent series by pre-Raphaelite Henry Holiday.  At first, only the Chancel (the part of the Chapel where the Choir resides) had coloured windows, the rest of the Chapel simply having clear glass, but through time all thirteen windows were filled with his work.

Henry Holiday editedHenry Holiday (1839-1927) was an artist of great skill and many talents.  He was trained by William Cave Thomas in 1852, and two years later he entered the Royal Academy School.  He made progress with his drawing and painting and was greatly influenced by the Pre-Raphaelites.  Millais and Ruiskin both encouraged him, praising his painting, and he was on friendly terms with Rossetti, Burne-Jones and Holman Hunt.

Following commissioning, Henry Holiday produced a vidimus (below, left) for approval.  Once the design was approved, a full-sized cartoon was drawn for every ‘light’ or opening of the window.

This vidimus and window shows the story of the three holy children, from the Book of Daniel: Shadrak, Meshak & Abednego, who had be flung into a burning fiery furnace because they would not worship Nebuchadnezzar.

O all ye works of the Lord, bless ye the Lord.
Praise Him and magnify Him for ever.

Project Development

Dynamic range

Human eyes have the fantastic ability of being able to handle a vast dynamic range -possibly well over 20 stops.  Thus a stained glass window can appear stunning to the naked eye with a range from almost clear glass to dark vibrant blue.  Sadly even the best cameras will only capture a small segment of this.

Dominic Price - Positions & Practice Oral Presentation

Each of the ten segments above is separated by 1/3rd of a stop.  It is clear that the white areas become washed out when overexposed by no more than 2 stops, but the blue areas require at least 3 stops more light in order to become visible.

Project Development

Three dimensions?

Outside access to the Chapel of St. Nicholas windows is not easy, so I have never DCP_5730 ce lrpreviously viewed them from that perspective.  However, closer examination of one of the windows dew me to venturing outside.  It appeared that the glass was layered.  Certainly not immediately obvious, but there are sections that clearly have more than one layer of stained glass, producing a three dimensional feel that is most apparent on this tiled floor section from ‘The Lord is my refuge and fortress’.  However, trying to photograph this effect as intended, is close to impossible.  The best I could manage was to demonstrate that there is a lower layer of lead.

From the outside, such features are evident on only two of the four accessible windows, but are significantly more obvious (and more abundant DCP_5720 e lrthose windows than is apparent from the inside).  Some of the double layers are in vivid, dark coloured locations – perhaps two layers of glass are necessary to achieve the deep blues, for example (although it is worth noting that not all vivid blues areas are double-layered).

Seen in its entirety from the outside, with the benefit of some highlighting, the images below show the extent of the double-layering.  When overlaid with a mirror image of the edited window, it is clear that this feature exists only in the darker areas or vivid colour.

IMG_2823 e cut out lr  IMG_2823 e cut out (with reverse view) lr

UPDATE: November 25, 2018

Further research reveals this process to be ‘plating‘ – a stained glass technique perfected by L.C. Tiffany in the early 1900’s.  Plating is the process of layering glass, one piece over another, to create shadows, contour and add depth to compositions.

Project Development

Harris Manchester College Chapel

IMG_2833 ce (low res)Dedicated in 1893, the College Chapel originally had plain glass windows, but this was gradually replaced by the current stained glass between 1895 and 1899.  They are all by Edward Burne-Jones and William Morris, making the chapel the only room in Oxford to be lit entirely by Morris/Burne-Jones glass.  So complete is this décor that even the organ pipes were painted by Morris & Co..

The orientation of the chapel is at odds with tradition: it is normal for the chancel and communion table to be situated at the east end of a chapel or church, but HMC Chapel was built with these at the west end.  For simplicity, I will refer to the actual compass bearings in this post.  My initial visit coincided with extensive cleaning work to the exterior of the roadside college buildings.  As a result, the east end window was under protective wraps.  This will be something for another visit.

12 impressDCP_5735 ce lrive pre-Raphaelite windows illuminate the chapel with each being composed of multiple lights.  The west window, installed in 1895, was the first to be designed and is far to complex to handle as a single image.  On this initial visit, I selected a small percentage of the window – just two representative lights:

At the top is a beautiful rose consisting of a circle depicting the Nativity of Jesus (BJ 285), surrounded by six angles: an obvious choice for photographing, not least because it contains no support bars, making post-production more straightforward.
HMC - Rose - Final (low res)

Central to the west window is a light depicting Jesus Christ, the Good Shepherd (BJ 399), in crimson, bearing a lamb.
HMC - Jesus - Final (low res)

Additionally, I photographed the second window, installed in 1896, depicting Generosity (BJ 398), in the person of St. Martin, dividing his cloak to shear with a beggar; and Courage (BJ 397), portrayed as a soldier, St. George, with shield and spear.

The complexity of design within St. Martin’s patterned cloak and armour was such that I failed to be able to remove all of the support bars – while I was able to edit out the 4th bar down and significant parts of the 1st and 3rd bars, 20+ hours of effort produced unsatisfactory results for the parts remaining, so the final image depicts the light complete with bars.

It is entirely coincidental that each of the lights photographed were designed by Burne-Jones.  On a subsequent visit, I must endeavour to capture one by Morris.

Project Development

St. Luke’s Chapel

Formerly the church of the Radcliffe Hospital, the chapel is now deconsecrated following the extensive redevelopment of that area.  Situated on the stunning Radcliffe Observatory Quarter, it now forms part of the University’s ‘Conference Oxford’ portfolio and is available to hire internally (within the University) as a small venue for meetings, receptions, small exhibitions and dinners.

Despite its diminutive size, it contains an impressive number of beautiful pre-Raphaelite stained glass windows, but their view in several instances is inhibited by the redevelopment of the chapel.  Additionally, access is far from perfect and on a subsequent visit I will need to attempt to engage the services of the University IT Support who have exclusive access to a mezzanine level (akin to an organ loft) that would provide a preferred vantage point.  Currently both images below are for reference only, the results of minimal editing.

The east window is incredibly elaborate, consisting of 15 lights depicting ten individual scenes from the bible.  Sadly this is backed by a protective mesh that detracts significantly from the visual impact of the window.  On this preliminary visit I captured the window in a single frame, but realise retrospectively that it will be better represented by photographing some of the individual scenes.
DCP_5829 ce lr

The west window is a magnificent rose, but the bottom is obscured by the mezzanine level.  Access to that level will allow the capture of the full window, but I am wary that such photograph would have to be taken with a very wide angle lens aligned precisely with the centre of the rose.
DCP_5857 ce lr

Project Development

Archive images – perhaps unnecessary?

It has always been my intention, when photographing stained glass windows, to produce two distinctly different sets of images:

  • the first to demonstrate as accurately as possible the full visual impact of the window (focussing on the main subject of the window, not necessarily including the window or light in its entirety; edited initially to capture the full dynamic range and then digitally corrected to remove any damage as well as removing the horizontal support bars).
  • the second image (or batch of images) would be of the entire window or light,  for insurance / historical / academic research archive purposes.

Various recent experiences suggest that I cease with this second exercise.  Unusually, I have received no follow-ups from my communications with three of the most appropriate bodies where archive work is concerned (The British Society of Master Glass Painters, the V&A Museum and York Glaziers Trust).  It would only seem sensible and appropriate to continue this practice only following their advice and recommendations.  My discussions with the colleges I have visited points towards an already established archive recording of the windows.

While I will not yet throw out the idea of taking archive images, it does appear unnecessary and unless I can gain a steer from a professional body, the action may prove fruitless.

Project Development

Digital removal of support bars

Henry Holiday cartoon windowRemoving the horizontal support bars from a stained glass window image is definitely contentious.  After all, the vidimus, (the approved design of a window; an example is shown to the left) will have included these metal bars – they are very much part of the design.  However, they do mask window details and while a necessary evil, do detract from the composition of the artwork.

I have worked hard to remove the support bars from each of the windows I have edited.  It is a laborious and time-consuming process, but so far I have been successful in this work and the results are pleasing.  However, thus far this removal has for the most part been straightforward with the support bars covering comparatively plain segments of the window.  Unfortunately this is not always the case, with some windows featuring support bars which cover intricate and complicated detail.

IMG_2927 CROP lr

In the portion of window above, the removal of the support bar would be straightforward where it covers the orange/red and blue material; the stair-runner would be rather more demanding as would the basket.  However, the construction of two dove’s heads in the absence of any reference material would be unbelievably difficult.

02 - Cropped - CROPI stand by my belief that the edited images are dramatically improved following the removal of the support bars.  Thus it remains my intention to remove them when and where possible.  Perhaps my choice of stained glass window within a chapel, where choice is available, should be driven to some extent by this factor.  Where this presents  an almost 03 - Completed - The Lord is my Refuge CROPimpossible editing challenge, such as the bird basket above, then it would seem appropriate to leave the support bars in situ.  Frustratingly, I am prompted to type this having spent in excess of 10 hours thwarted by one section of support bar within an image from which I had already removed 60% of the bars!