Horizon Imaging

Ultra high-resolution imagery printed onto scaffolding wrap in the UK Foreign and Commonwealth Office

The Project

Earlier in the year we were presented with one of our most challenging projects to date — capturing a 300 megapixel architectural photograph from 5 metres above the Grand Staircase inside the UK Foreign and Commonwealth office! Never a company to turn down such a challenge, we eagerly accepted the project. 
The ceiling above one side of the Grand Staircase was in need of renovation and the only way to achieve this was to completely scaffold the area from floor to ceiling. However, as the Grand Staircase is one of the most beautiful and photographed areas of the Foreign and Commonwealth Office (FCO) — and one that is often used as a backdrop for photographs of official visits (see below) — the FCO understandably wanted to keep the unsightly scaffolding hidden as much as possible
Boris Johnson and other senior diplomats standing on the Grand Staircase in the Foreign and Commonwealth office. Click to enlarge. Image credit: AFP 

Enter scaffolding-wrap experts Tufcoat. As well as being able to wrap scaffolding structures of any size or shape using special weather-resistant heat-shrunk plastic sheeting, they are also able to print onto this sheeting in full colour. When printed with suitable imagery, this allows scaffolding structures to blend in with their surroundings, be it mimicking the external facade of a building, or in this case, mimicking the part of the Grand Staircase which would be hidden by the scaffolding. 

Challenge 1 — Perspective

The first challenge was deciding how to capture the imagery to create the most convincing ‘camouflage’ effect for the scaffolding once it had been wrapped. The problem with fixing a giant 2-dimensional poster into a 3-dimensional space is that the perspective of the resulting image would only look ‘correct’ when viewed from the point in space where the imagery was originally captured from — eg. the front of the camera’s lens. As such, it was accepted from the outset that the realism of this ‘camouflage’ would never be 100% perfect — but that anything was preferable to leaving the scaffolding exposed! 
One aspect of the Grand Staircase which made the task of capturing the imagery slightly easier was the fact that the room is, for all intents and purposes, entirely symmetrical — if you drew a line along the centre of the stairs in the photograph above, this is the line of symmetry for the whole room. This meant that by capturing an image of one end of the room and then flipping it horizontally, the resulting image would look almost identical to an image taken of the other end of the room. This turned out to be very useful, as by the time we were commissioned to take the imagery, the scaffolding was already fully installed, meaning it was impossible to photograph the side of the staircase which would be replicated by the printed wrap, as it was completely obscured! 
It was decided that the imagery should be taken from roughly the height of the upper balcony (as this is where the grandeur of the Grand Staircase can be most readily appreciated) and aligned centrally between the windows and upper balcony (due to the natural symmetry of the room). With the scaffolding already in place, a point was found on the second level of the scaffolding structure where the camera could be mounted to take the photographs. You can see this in the images below: 
Behind-the-scenes photographs of our camera attached to a panoramic tripod-head, and then firmly attached to the scaffolding above the Grand Staircase of the Foreign and Commonwealth Office. Click to enlarge. 

Challenge 2 — Resolution

The next challenge was how to capture an image with a enough resolution that it would still contain sufficient detail and clarity when the image was printed onto the plastic wrapping … all 19 x 9 metres of it! As a result of our expertise in producing virtual tours, we have all the necessary hardware and software to seamlessly stitch together overlapping images, allowing us to produce high-resolution spherical images which allow the user to look in any direction in the virtual tour environment
The most important piece of equipment for achieving this is the panoramic tripod head which can be seen in the images above. This holds the camera in such a way that it is always rotated around the ‘entrance pupil’ of the camera / lens combination. The ‘entrance pupil’ is the infinitely small point in space where the rays of light from a scene first cross inside the camera’s lens, and this is the point where the photographs appear to be taken from. If the camera is not rotated around the entrance pupil, the perspective of the scene will very subtly change as the camera is moved, making it almost impossible to seamlessly stitch together the resulting photographs. 
A useful application of the same hardware and software we use for creating virtual tours is to create images of incredibly high-resolution using a camera with a relatively low-resolution sensor. Rather than taking a single image of the Grand Staircase with a 10mm lens, we took 20 images with a 35mm lens and then seamlessly stitched the images together. The camera we used to take the images has a resolution of18 megapixels, or 5184 x 3456 pixels. But by stitching these 20 images together, we were able to produce a single image with a resolution of 302 megapixels, or 22643 x 13354 pixels! This level of quality ensured that the final printed wrap looked fantastic, even when standing a few metres away from its surface (as most onlookers would be). 
The final 302 megapixel can be viewed below, albeit in a low-resolution, web-friendly format. Also included below are three 100% crops from the 302 megapixel image, showing the incredible level of detail that was captured. 
The first image is the finished 302 megapixel image which was printed onto the plastic scaffolding wrapper. The second, third and fourth images are 100% crops from the 302 megapixel image, with inset diagrams showing where the crops have been taken in the original image. Click to enlarge. 

Challenge 3 — Dynamic Range

Capturing an image of sufficient resolution to look good on such a large print was one issue. Working within the limited range of brightnesses that can be captured by a digital camera in a single exposure was a completely different challenge. 
Unlike the human eye which can process up to 20 ‘stops’ of dynamic range, most cameras can typically only capture between 11 and 14 stops of dynamic range. A ‘stop’ is a term used to describe a quantity of light — if you increase an exposure by one stop, you are letting twice as much light hit the camera’s sensor. Dynamic range is a way of describing the range of brightnesses which can be captured and processed by a camera’s sensor — from the brightest light source (eg. a bright lamp) to the darkest shadow (eg. underneath a table in the corner of a room). Put simply, if the dynamic range of a camera’s sensor does not equal or exceed the dynamic range of a scene to be captured, the brightest areas will be ‘burned out’ (recorded as pure white pixels), and the darkest areas will be ‘crushed’ (recorded as pure black pixels). 
The easiest solution to overcome this problem, at least when photographing a static scene like the Grand Staircase, is to take multiple images at different exposure levels, and then blend the resulting images together. In other words, take a correctly-exposed image, an over-exposed image (too bright), and an under-exposed image (too dark), thereby capturing detail in the darkest areas of the room (in the over-exposed image), and in the brightest areas of the room (in the under-exposed image). This technique is known as Exposure Fusion, or High-Dynamic-Range (HDR) Imaging.  
So, for each of the 20 positions where we took photographs, we actually took 3 photographs at 3 different exposure levels — so, 60 photographs in total. The dynamic range was then ‘compressed’ in specialist processing software to produce a final image with fine detail in all areas of the image — both in the brightest and darkest areas of the room. The animations below show how much extra detail was retained in the final HDR image versus using only a single exposure. 
Differences between the final Exposure-Fused / High-Dynamic-Range (HDR) image and a single exposure of the same scene. Click to enlarge. 

The Result

Once the enormous plastic wrapping had been printed with the imagery we had provided, it then had to be painstakingly stretched over the scaffolding structure and then heated to make the plastic taut and crease-free. 
The time-lapse video below, produced by Tufcoat, shows how the wrapping was attached to the structure — click the play button to watch the video: 
Time-lapse video produced by Tufcoat showing how the plastic wrapping (printed with our imagery) was attached to the scaffolding structure in the Foreign and Commonwealth Office. Click the play button to watch the video, and be sure to click the rectangle symbol in the bottom right to watch the video full-screen. 
Unfortunately we have yet to revisit the site since the wrapping has been applied to the scaffolding, but we have been sent the following photographs which given an idea of what the finished installation looks like: 
Time-lapse video produced by Tufcoat showing how the plastic wrapping (printed with our imagery) was attached to the scaffolding structure in the Foreign and Commonwealth Office. Click the play button to watch the video, and be sure to click the rectangle symbol in the bottom right to watch the video full-screen. 
As well as this main scaffolding wrap, we also captured similar high-resolution imagery for 6 other wrapped faces of this scaffolding structure — on both the ground and first floors — using a very similar process. 
Tufcoat have now used our services a number of times — both to take high-resolution imagery to print onto their scaffolding wraps, and also to document existing installations with elevated photographs. They have always been delighted with the results we have produced for them, and they recently sent us this kind testimonial:  
“We’ve worked with David on several occasions over the last 2 years. 
In both documenting finished construction projects to photographing internal and exterior architecture allowing us to create realistic shrink-wrap building wraps, his work ethic is highly admirable. 
David’s knowledge of photography and dogmatic approach to producing a high-quality image is first class. 
Horizon Imaging’s array of tools and gadgets have been of great use to our projects particularly the mast photography, which has proven benefits creating stunning high-level imagery where the use of a drone is impossible.” 

Do you need to capture ultra high-resolution imagery of one of your projects? Or perhaps your projects are so large that they would benefit from being photographed from an aerial viewpoint? We have the technology and expertise to deliver professional imagery in these applications, and more. Drop us a line today and we’d be delighted to discuss your requirements with you.