Harold Whitehouse and his camera
During the last 30 years of his life the distinguished bryologist Harold Whitehouse took thousands of photographs, mainly in the British Isles, but also in Continental Europe, Canada, New Zealand and the Pacific. By the time of his death in 2000 he had photographed approximately 80% of the British bryophyte flora. These were not ordinary photographs but stereo macro-photographs taken using a specially constructed camera designed and built by his wife, Pat. His collection of slides passed to the BBS and thence to the National Museums and Galleries of Wales, based at Cardiff, where the BBS herbarium is housed.
Harold Whitehouse wrote about his camera and stereo-photographic techniques for an article in the Bryological Times which is reproduced, with permission, below.
He long wished for the photographs to be published, but it was not really until the widespread use of digital images that this became practical. In 2000, Jonathan Sleath (editor of the BBS website at the time) set about scanning the best examples of each species, prepared colour anaglyphs, and with the help of his son Oliver constructed a series of web pages to display them. Jonathan documented the technical challenges of scanning and making the images available online, and you can read about this below.
These web pages have now been archived and the images are no longer available to view online here because of the technical difficulties of displaying them as they need to be viewed for stereo effect. However the scanned images are available to download for those who wish to try.
Sadly, camera technology and image quality have moved on a great deal in the years since these photographs were taken. They now represent a rather imperfect tribute to a man who commanded the respect and affection of his many friends.
The copyright for these images rests with the National Museums and Galleries of Wales. For personal use, the images may be reproduced unconditionally. For academic publication, the images may be reproduced provided that NMGW is notified and acknowledged. For commercial publication, the images may be reproduced only with the formal permission of NMGW. Any requests for permission for their reproduction should be made to The Curator, The Herbarium, The National Museum & Gallery, Cathays Park, Cardiff, CF10 3NP.
by H.L.K. Whitehouse
Stereoscopic photography has considerable advantages over ordinary photography for recording small living organisms in their natural environment. The subject is not lost in its background and the characters for field identification are revealed.
For stereo photography of bryophytes I have used a camera designed and constructed by my wife Pat just before she died in 1988. It consists of an old, ordinary, single lens, 120 roll film ‘Agfa Isola’ camera in which she extended the lens barrel and fitted two lenses from a Nimslo camera. These lenses have a focal length of 30 mm. They are set with centres 12 mm apart. To achieve this small separation, one side of each had to be ground away. The stops fitted are f80, giving an apparent depth of focus of 10 mm. A flash-synchronised Prontor shutter from another camera was fitted in-front of the two lenses to expose both images simultaneously. A septum (dividing plate) was constructed between the two lenses extending to a plate fitted into the back of the camera. This plate masks off 12.5 mm of the opening at each end, reducing the length of film exposed in each photograph from 56.5 to 31.5 mm. In this way, pairs of images are obtained with each exposure measuring individually 31.5 mm in height and 26 mm in width.
After Pat’s death, David Burder fitted a bracket to point a Nimslo flash gun down so that it is only about 55 mm from the subject, and adapted the flash gun to work at maximum output. He also fitted two antennae’ to indicate the plane of focus, which is about 30 mm in front of the shutter: The camera measures 140x Il0x 100mm and so fits into a large pocket. It weighs 360 g, plus 200 g for the flash.
Using Fujichrome 120 professional film, ASA 100, 25 stereo pairs can be obtained on each film by exposing at the first of each trio of dots on the backing paper as well as at the 12 numbered positions, with an extra exposure half a turn of the winding knob after the last number. For viewing, the photographs are attached to aluminium foil mounts measuring 101 x 41 mm (Fig. 1). These have openings 23.5 mm high and 21 mm wide placed with their centres 62 mm apart, which is slightly less than the average human eye separation. The area of the subject seen after mounting is about 10 mm wide in the foreground and 15 mm in the background, implying a magnification of twice life size on the film.
The first step in mounting each stereo pair is to choose the most interesting part because, as already indicated, the transparencies are larger than the openings in the mounts. In the vertical direction there will be 8 mm to be masked off. The scope for choice of field in the horizontal direction is more limited. The second step in mounting is tedious, as the transparencies have to be co-oriented with precision, so that (a) there is no displacement up or down of the one image relative to the other, and (b) the displacement to left and right is such that the three-dimensional image just reaches the ‘stereo window’. Viewing a mounted stereo pair gives the impression of looking through a window. The ‘window’ is formed by the fused images of the openings in the mount. As these are 62 mm apart, the two images of the nearest part of the moss or liverwort should also be 62mms apart The images of more distant parts of the subject will have a greater separation. Moving one of the transparencies laterally relative to the other will bring the fused image forward or backward. It is acceptable visually to have a central part of the fused image coming through the window, that is, a separation of less than 62 mm between the images on the two transparencies, but it looks unnatural to allow this to happen at the edge, as the fused image will then appear to be cut by the window frame. In mounting the photographs it is not necessary to make measurements of their separation: the best relative position of the two photographs can be judged from the 3-D image. I have a mounting device, with horizontal lines on ground glass, to facilitate mounting the stereo pairs. Once the transparencies have been correctly co-oriented, they are secured to the aluminium frame with translucent tape and can be viewed through a stereoscope. For greater protection, glass covers are available, which can be held in place with silver polyester tape.
The chief difficulty that I have encountered in stereo photography of bryophytes has ken how to avoid getting too much depth in the photograph. Depth needs to be limited not merely because parts of the image will be out of locus but also because of 3-D problems. With a large moss cushion, the two images of distant parts of it will be unacceptably far apart, that is, more than ca. 65 mm when the foreground is close to 62 mm separation. One cannot fuse such widely-spaced images without eyestrain. Large mosses may form a tuft that is sufficiently dense to prevent one seeing too far into it.. Alternatively, it may be necessary to remove the background material and photograph just the superficial 5 or 10 mm. If this is hand-held, the background will appear black. This is preferable to inserting a sheet of black paper or card into the tuft, as the camera will reveal this.
Another problem arises when photographing glossy surfaces, such as wet leaves and some thallose liverworts which, even when dry, reflect too much light and over-expose the film. A single thickness of white polythene (polyethylene film) placed over the flash head will reduce the light intensity sufficiently.
Aquatic bryophytes pose difficulties for photography because of reflection of light from the water surface. If the flash gun is hand-held, the angle between it and the axis of the camera can be varied and a position found that avoids such reflections. With bryophytes in rock crevices the flash gun may also need to be hand-held in order to illuminate the plant. A narrow crevice may be inaccessible for the camera and the plant will then have to be removed for photography.
I have now photographed stereoscopically about 400 species of bryophytes, mostly in Britain, but some in Portugal, Spain, France, Canada and the U.S.A. I hope soon to start publishing them.
Excellent stereo photographs of bryophytes can be obtained without a stereo camera. All that is required is a close-up attachment to an ordinary single-lens camera, and a small tripod with a slide bar (Fig. 2). This is an angled shelf of wood or aluminium clamped to the tripod.
The camera is placed on this platform, which should be horizontal and perpendicular to a line joining camera and subject. Two exposures are made, and before the second one the camera is moved along the shelf (Fig. 3) a distance equal to one thirtieth of the distance between the lens and the nearest part of the plant to appear in the photograph. If flash is being used to illuminate the bryophyte, the flash gun must not be mounted on the camera. A second tripod to early the flash would be ideal, as the flash gun must not be moved between the two exposures. If 35 mm film is used, mounting the stereo pair for viewing is straightforward. One possibility is to mount the photographs in ordinary 50 x 50 mm frames and look at them through a pair of viewers held together with a rubber band. Alternatively, the pair of photographs can be attached to a 101 x 41 mm foil mount. These have slots to take 35 mm transparencies. They can then be viewed with a stereoscope.
Stereo photographs can be projected for an audience. A double projector to take the 101 x 41 mm slides is needed, or two single projectors if the transparencies are mounted in individual 50 x 50 mm frames. The projectors have polarizing filters. A metallic screen is used and the audience wears polarizing spectacles.
I thank David Burder, Chris Preston and Line Rochefort for helpful comments on this manuscript. I am grateful to David Burder for permission to publish the drawings, which are taken from his manuscript entitled ‘Stereoscopic projection using two standard projectors’ (Fig. 1) and from the publication ‘Photographing in 3-D’ (figs. 2-3).
(Reproduced, with permission, from The Bryological Times No. 57/58, 1990 )
by Jonathan Sleath
I have included what I felt to be the best image of each UK taxon, even if it was photographed outside the UK. There is also a selection of interesting non-UK plants. The field of view of each image is between 10mm and 15mm in width.
Almost all species have a left and right image displayed side by side for fusion into a stereo image by those who are able to cross their eyes at will. There are also anaglyphic images to be viewed with red/green spectacles, with the image for the left eye being red, and for the right eye being green. The colour anaglyphs contain extra colour information, but can be uncomfortable to view in cases where there are large areas of saturated colour. In these cases a monochrome anaglyph has been prepared as well.
The stereo slide bequest contains several thousand transparencies, all of which are unique. Some are unmounted, but most are in aluminium mounts with handwritten labels.
Some of these have been further strengthened with glass to make them rigid enough to be viewed in a hand-held stereoscopic slide viewer. There was no catalogue for the whole collection, so I sorted them by hand and for each UK taxon represented chose a single slide that I felt best portrayed the plant in the field. I also made a selection of some of the non-UK species, and an example of each species represented in the collection of photomicrographs of gemmae (mainly protonemal). Many of the images are of poor quality, but I felt that it was better to show a poor image than no image at all, and there were few species where I had to reject all the slides.
The size of each individual transparency is approximately 21mm x 23mm. Because of the non-standard format of the slides it was impossible to scan them using a dedicated 35mm slide scanner. I therefore had to use a flatbed scanner with a transparency adapter. The highest resolution available was at 1200 dpi, and I used the Epson 1200 Perfection Photo for this. After some basic image processing in an attempt to improve the clarity, the left and right images were saved as high quality JPEG files with a size of approximately 1000 x 1000 pixels. For display on HTML pages they were further resized to a height of 300 pixels, an unsharp mask applied, and a border made using the batch processing facility of Photoshop.
To manufacture the anaglyphs I used a freeware program called Anamaker (from Takashi Sekitani at www.stereoeye.jp) which splits the red/green/blue components of the stereo pair and fuses the red information from the left image with the green/blue (cyan) information from the right image to make a colour anaglyph that can be viewed with red/green spectacles. The best images to make anaglyphs from are those that have little contrast, a rather washed out appearance due to reduced colour saturation, and a light-coloured background. Because the slides were taken with flash, they have a black background and high contrast so are rather unsuitable to begin with. The only exception is Campylostelium saxicola, which is an old slide taken in 1961 by Pat Whitehouse, and makes a very good anaglyph.
Where there are large surfaces with saturated colour, the colour anaglyph can be very uncomfortable to view because of the phenomenon of retinal rivalry. In these cases I have also made a monochrome anaglyph where the left/right images are simply converted to red/cyan. These are much easier to view, although the colour information is lost. It is possible to reduce the saturation in the original colour anaglyph, but the more this is done the greater the loss of the stereo effect. The other main problem is that of ghosting, where a ghost image of a pale object against a black background is seen, for example when setae are photographed with flash. This will always happen, and is very difficult to correct.
Single pairs of red/green spectacles are usually available with childrens’ 3-D books. There are many stereoscopic resources available on the internet giving details of techniques and materials. A good starting point with many useful links is http://www.stereoscopy.com/.