The Royal Photographic Society
Newsletter November 2004
Editorial
The big news this time is the
holographic portrait of the Queen on display at Buckingham Palace. Plenty of
important people have had holographic portraits made, including the late Ronald
Reagan, but this is the first royal one. It is a stereogram, larger than life
size, illuminated from behind by a vertical line of blue LEDs. It was
commissioned by the Jersey Heritage Trust as part of the celebrations of the island’s
800 years of allegiance to the English Crown.
The job went, more or less by
default, to Chris Levine (professional holographers are thin on the ground in
the Channel Islands), who understandably went to the experts, Rob Munday and
Jeff Robb of Spatial Imaging, for the realisation of the project. Rob undertook
the development of a new and greatly improved 2.5 m linear-rail digital camera
system shooting the images at 30 frames per second with the camera rotating to
point towards the subject, and with new software to correct keystoning effects.
The project attracted wide publicity, particularly for Chris himself, but the
role of the others has been seriously underplayed in the media – not only that
of Rob and Jeff, but of Nina Duncan, who was responsible for the lighting,
Richard Bainbridge who enhanced the raw images, and John Perry of Holographics
North in the USA, who carried out the mastering. The Trust has produced a DVD
about Jersey, featuring the making of the hologram, but although the protagonists
appear fleetingly in the recording of the event and their names appear in the
final credits, they are not mentioned in the commentary. The DVD isn’t
generally available, as it was put together before the project was complete,
but I understand that a final version will eventually be released. Full details
of the way the project was carried out appeared in Holography News Vol 18 No 7
(Aug 2004).
As this is the last
Newsletter before the festive season (which in my town seems to start in
mid-September), I should like to take the opportunity on behalf of all the
Committee members of wishing you all the very best for Christmas and the New
Year, and may your lasers never grow dim!
Michael Talbot: Holographic Universe
Harper Perennial, pbk, ISBN
0-06-092258-3, $11.20 from Amazon
A few weeks ago a
correspondent drew my attention to an anonymous essay entitled The Universe as a Hologram, which
appears on a number of websites, for example http://twm.co.nz/hologram.html,
where it is suggested that it may have been written by one Michael Talbot. I discovered that Talbot had written several
books, in particular one called Holographic
Universe, and obtained a copy of it. Although plainly not about
holography per se, in view of its philosophical connections with holography I
thought it needed a critical review.
First, a bit of background.
From Isaac Newton to Linus Pauling, distinguished scientists have often held
odd beliefs that have been widely accepted at the time, largely owing to the
standing of the person concerned. Some lesser lights, such as René Blondlot,
perpetrator of the M-ray scandal of the early 1900s, even acquired an
international reputation (albeit brief) entirely through their eccentric ideas.
David Bohm, a brilliant physicist formerly associated with the development of
atomic energy, and no doubt in line for a Nobel Prize until McCarthy’s
inquisition forced him to resign his post (he refused to betray his friends),
finished up at Birkbeck College in London, where his work on entanglement theory
earned him an FRS. His particular obsession was what he termed ‘the implicate
order’. The hypothesis was that underneath the complexities of quantum physics,
with its inexplicable uncertainties, awkward paradoxes and uncomfortable
infinities, lay a kind of continuum – the implicate order – that involved everything that existed in the
universe, including human consciousness. He invoked the hologram as a metaphor
to illustrate his thesis (though perhaps Carl Jung’s ‘universal unconscious’
might have been a better one). This ‘universal hologram’ concept was taken up
by a number of other people and applied to disciplines other than cosmology and
quantum physics. One of these was Karl Pribram of Stanford University, a
neuropsychologist whose main research was into the memory of trivial lists by
visualisation. He had been much influenced by the work of Karl Lashley, who in
a lifetime of research had spectacularly failed to find specific centres in the
memory (of rats), and had concluded that memory was distributed more or less
uniformly over the whole brain. Pribram hypothesised that memory was stored in
the brain literally in holographic form. In spite of this misunderstanding
about the nature of holographic coding, which isn’t uniform (in a primary hologram the viewpoint is coded
locally, and in an image hologram everything
is coded locally), Pribram’s beliefs have gained some public currency,
particularly in the United States. The anonymous website postings may be
contributing to this: apparently the answer to life, the universe and
everything is a hologram. [Note: Hitchhiker
aficionados are aware that the correct answer is 42, and the ultimate
question was ‘What do you get if you multiply 6 by 9?’ This makes sense if you
appreciate that the lifeforms who asked the question had seven fingers on each
hand and thus counted in fourteens.]
Michael Talbot’s book manages
to draw a tuna-sized red herring across this whole murky area. The book is not about holography, although the
words ‘holography’ and ‘hologram’ appear on almost every page. It is almost
entirely devoted to discussions of psychical phenomena: precognition, telepathy
and psychokinesis, along with out-of-body and near-death experiences, all
matters on which Talbot is an authority. Each of these subjects is dealt with
in considerable depth, with numerous anecdotal examples and copious references.
He ties in all these phenomena with an extradimensional continuum that he calls
‘the universal hologram’, apparently taking Bohm’s metaphor literally. The
reason for this is hard to understand, as he begins the book with an excellent
description of the way a hologram is made and the image reconstructed. I
suspect that he may have had some help over this, as he later uses terms such
as ‘frequency’, ‘radiation’ and ‘energy’ in a way that shows he has little or
no understanding of their scientific meaning. Apart from this misuse of
scientific terminology, however, the book is well written and self-consistent.
The author claims to be a sensitive, and to have had a large number of
psychical experiences himself. The 500-odd references quoted are almost all
from publications on psychical matters or from personal communications,
including a number from both Bohm and Pribram.
Although the early discussion
about the ‘universal hologram’ looks at Bohm’s metaphor in perhaps too literal
a way, it is Pribram’s model that holds sway over most of the book. The trouble
is that if one takes a holographic model and tries to use it to predict
phenomena (for that is what a model is used for) it simply doesn’t work, either
for the filing of information in the brain or for its retrieval. Recent
research has shown that information in the human brain does have a high degree
of localisation (pace Lashley),
and that a model of a computer database, while still not entirely satisfactory,
answers more questions than a holographic model can.
By the way, David Bohm’s
thesis, to which New Scientist was moved to devote a long and serious article,
is expounded comprehensively in his book Wholeness
and the Implicate Order (Routledge & Kegan Paul). Unless you have
more than a nodding acquaintance with quantum physics you may find you need to
skip some bits. You can find out more about Pribram on
http://twm.co.nz/Pribram.htm.
Graham Saxby
Holograms in Print
In June 1983 a new era in
illustration began when Amateur
Photographer published its first three-dimensional hologram cover, a
small two-colour image designed by Ken Harris. The following year The National Geographic Magazine used
an embossed hologram of the American eagle on its cover, and with a circulation
of several million the concept spread worldwide. These examples were not quite
the first, as Science Year had
included a laser transmission hologram as early as 1967, and in 1971 Les Prix Nobel had a silver halide
reflection hologram bound in to mark Denis Gabor’s Nobel award, but these were
comparatively small-scale publications. National Geographic’s special on
holography was followed in November 1985 by a holographic image of a
two-million-year-old skull, and in December 1988 by a full holographic cover
marking the beginning of their second century of publishing. Significantly,
holography was not mentioned in either issue, by now being taken for granted.
In the meantime there had
been some landmark publications. The
Mirrorstone, published by Jonathan Cape in 1986, included a number of
embossed holograms that were hot-foil stamped as part of the illustrations. New
Scientist included a holographic image of Isaac Newton on the cover of an issue
featuring applications of holography, and the reggae group UB40 released an LP
album with a limited edition cover sporting an embossed hologram containing the
album’s title ‘UB44’ and
nothing else: it quickly became a collector’s item. Zebra Books in the USA
began to use a small holographic logo on the front of their pulp fiction, to
distinguish their work from imitators. In November 1988 the RPS Journal was
largely devoted to creative holography, and featured a mass-replicated silver
halide hologram by the fledgling Applied Holographics Company.
It soon became clear to the
comic book trade that holography and comics were made for each other: the
flashy silver foil and rainbow colours of embossed holograms blended well with
action-packed graphics and bold typography. Designers could now integrate
holography with other artwork in a truly imaginative fashion. A number of
British publishers took up the idea, using holographic illustrations in
children’s books in a more gentle style. Science fiction and horror were also natural
bedfellows for holography, and quite a number of paperbacks appeared containing
two-channel images of dinosaurs, aliens and ghouls. In the more specialised
realms, various holographic journals and trade magazines used holograms as part
of their content and for advertising purposes.
Holography, perhaps more than
other media, is at the mercy of the vagaries of fashion. Apart from the
omnipresent security labelling and fancy packaging there seems to have been a
lull in the use of holograms in printed matter; but since, in my opinion,
illustration uses holography in one of its most appropriate ways, I hope and
expect it to regain its rightful place before long.
Jonathan Ross
Editor’s note: The full text
of this article, with illustrations, can be seen on Jonathan’s website
http://www.holonet.khm.de/jross/holosinprint/index.html
An unusual method for lighting small
holographic subjects
The arrival of the twentieth
anniversary of the infamous Brighton Bomb reminded me of what I was doing when
I heard the news over the radio (Brighton is my home town). At the time I was
working on a curious holographic experiment in a converted stable in the serene
surroundings of Braxted Park, Essex.
At that time Applied
Holographics Plc (now AOT) were pioneering on that site the world’s first mass
production of small Denisyuk holograms on Ilford holographic roll film, using
ruby pulse lasers and a step-and-repeat exposure regime in what was essentially
a holographic photocopier, the ‘object’ being a master Denisyuk hologram. In
order for such a master to reconstruct a bright image when illuminated with the
original laser wavelength it is necessary to use a processing method that
doesn’t distort the fringe structure in any way; I had developed the
appropriate chemistry a year or two earlier.
(Note: The usual processing
formulae for a display reflection hologram shrinks the emulsion and ‘chirps’
the fringes, i.e. varies their spacing slightly throughout the emulsion
thickness, so that with white-light illumination a broader range of wavelengths
is diffracted and the image is brighter than it would be with a more
monochromatic image.)
Applied Holographics was
interested in my idea of being able to use a horizontally positioned master
hologram as a means to illuminate the sides of a small solid object placed on
it without the need for auxiliary reflectors, so that comparatively rapid
production runs could be made. Thus the master hologram could be made
specifically to act as a holographic optical element (HOE), if processed as
described above to resonate at a matched wavelength. So for several days I was
given the use of an outhouse equipped with an isolation table and a reliable
HeNe laser, and the assistance of their young physicist Dinesh Padiyar, to show
that the idea would work. As I wanted to make the initial demonstration as
mundane as possible I chose to use as my starting object an ordinary white
plastic coffee cup from the drinks machine, and made a Denisyuk master hologram
(H1) using a single beam from almost overhead, with the laser
temperature-stabilised to give maximum coherence length, in order for all the
multiple reflections inside the cup to register. I processed this master
hologram using my non-shrink formula. I then made a copy of this H1 turned over
in pseudoscopic mode with a gap between the two plates sufficient to give an
orthoscopic real image (H2) of the cup.
I then needed to see how
these holograms would work as reflectors, with a small object placed inside my
(holographic) coffee cup, when I made a further single-beam hologram (H3). As
object I chose two AA batteries standing up side by side on a horizontal glass
plate under an almost vertical expanded collimated beam. Naturally, with the
laser as the sole source of illumination the battery images would be completely
dark on the side away from the beam; but if the supporting glass were to be a
real-image reflection hologram, the image itself would provide fill-in
illumination for the object. This illumination proved very feeble from the H1
virtual image, and even more so from the H2 orthoscopic real image, but it was
greatly improved when I used the H1 turned over to give a pseudoscopic real
image.
Analysing that situation, one
cannot expect the orthoscopic real image cup to behave like the original cup,
which had tapering walls that would scatter light onto the object, plus light
back-scattered from the cup floor, whereas with the real image any light can
only come up from the plane of the hologram by diffraction. The image of the
cup floor was focusing light only round the base area, and the image of the
tapering walls was contributing very little, although when viewed from overhead
it looked as if the object were sitting in the original cup (in that
wonderfully clear illusion that you get when looking at a laser-lit reflection
hologram). On the other hand, the illumination from the pseudoscopic H1 image
would undoubtedly be better, because the floor of the cup had now become the
roof of a tower-like image that focused light to a central plane some inches
above the hologram. Thus the hologram, here used as an HOE, was an improvement
on the actual cup.
In realising this technique I
have to acknowledge the earlier work of John Webster, then at the CEGB
Marchwood laboratories, who had published the idea of making a hologram of a
diffuser plate and using this as a diffuser for laser light that would not
depolarise the light as would the original diffuser plate (unpolarized
illumination produces inefficient fringe formation). In the same way, my
holographic cup was itself acting as an efficient diffuser without causing any
depolarising of the illuminating light.
Jeff Blyth
Holography in the field
For some time we have been
planning to demonstrate simple hologram making to children, and working towards
making a basic kit capable of being transported, set up and used to make a
Denisyuk hologram in a variety of venues and under different conditions. Our
first experiments used a modified laser pointer and some old Agfa film cut into
2.5-inch square pieces, held between two pieces of 5 × 7-inch glass (from clip
frames) hinged together with tape. We didn’t use index-matching fluid, as this
was a complication we wished to avoid. The film holder was placed in a
horizontal frame with the object on top, and the laser was positioned about 12
inches below the frame to project a divergent beam at an angle of about 45º to
the film.
The film was pre-swelled in
5% triethanolamine (TEA) to increase its sensitivity and shift the image colour
towards green. The exposure was 5 seconds, and the film was processed in
ascorbic acid/metol developer and rehalogenating bleach.
The results obtained in the
darkroom were fairly good, so, with a camping weekend planned for the August
public holiday, we thought we would try under more difficult conditions. The
‘field’ where we camped was in the middle of a wood, off a minor road in
Dorset, with a muddy stream but otherwise no water, nor any electricity supply.
The awning of our caravan was used for the experiment, so we had to wait till well
after sunset, but before the full moon rose over the trees. The ‘safelight’ was
a fluorescent torch with a green gel wrapped round the tube.
The result was not the
brightest hologram in the world; but the object, which included some text in
white Letraset on a glass plate, and a representation of the Olympic rings made
from five steel washers, was clearly visible. Has anyone else made a hologram
in a field, with no running water or electricity – or was this a world first?
Bob and Molly Gibson
Department of Partly-Baked Ideas
A couple of issues ago the
DPBI discussed corner cubes (which, as Jeff Blyth pointed out, should really be
called ‘cube corners’) and other polyhedra. Owing to a temporary breakdown of
communication between brain and fingers, part of this item was garbled. The
corrected version is that Euler’s theorem states that if you take the number of
faces of a polyhedron and add it to the number of vertices, the answer is
always two more than the number of edges, so for a cube we have (for F + V –
E), 6 + 8 – 12 = 2. (The rest was correct.) I don’t know the proof of the
theorem, but there are two somewhat curious exceptions, namely the great
dodecahedron and the small stellated dodecahedron. These are duals of each
other: a dual of a polyhedron is obtained by replacing the vertices with sides
and vice versa, a simple example being a cube (F = 6, V = 8) and an octahedron
(F = 8, V = 6). The two polyhedra are produced by extending the sides in the
former case, and the edges in the latter, until they meet, which means that
although each has 12 sides and 30 edges as in a simple dodecahedron, the sides
intersect one another and there are only 12 vertices in each.
They are elegantly beautiful
solids, and have appeared more than once in the works of both Salvador Dali and
Maurits Escher. In spite of the re-entrant angles you can construct each from a
single sheet of cartridge paper. But if you take F + V – E the answer comes,
not to 2, but to – 6. This led the Swiss mathematician Ludwig Schläfli (co-inventor
of elliptical geometry) to assert, somewhat rashly, that they could not exist.
Mind you, if you count all the re-entrant faces, edges and vertices separately
the answer comes out right. If you want to know more about this fascinating
area, including how to construct these polyhedra, you will find the whole works
in Mathematical Models, by HM
Cundy and AP Rollett (Tarquin Pubs) (copies available from Amazon).
It has often been said that
you can make a hologram of anything you can see, given the right equipment (and
a good many things you can’t
see, too). This applies to holograms of optical components: a reflection
hologram of a concave mirror will focus light just like the original. However,
if you make a straight Denisyuk hologram of a corner cube it doesn’t behave
like the original device, and the DPBI is intrigued by this. As mentioned in an
earlier report, when you look into a corner cube you see an inverted image of
your eye. But this doesn’t seem to happen with its hologram. Something seems to
be going on between the various sets of fringes generated by the multiple
reflections, and the result seems to warrant some further head scratching at
the DPBI.