Page 28 - Studio International - February 1970

1. The image formed is a mapping or collap- because of this, and not for the purely visual plicitly to holography in attempting to model
sing of three dimensions on to two. If you effects of holography, that I have suggested a type of memory mechanism continually
move your head as you view the image, the it will be as important as photography has tuned by inputs to process further inputs.?
normal parallax effect is apparent: that is, the been. Incidentally, it is now necessary to I do not pretend to have done more here than
relative positions of the objects appear to categorize the kind of holography practised graze very ignorantly the difficult subject of
change. It is possible to move so as to see, for by Benyon as 'optical holography', as opposed interference patterning. But it seems likely
instance, a background object which is to acoustical holography, in which a pure that holography as a principle is highly
blocked by a foreground object. tone of sound instead of a laser beam is used relevant to the process whereby ordering and
2. If a hologram is broken into pieces, each to create a hologram.3 organization emerge from the totality of
piece can reconstruct the entire original As I have already suggested in relation to physical interaction. Laser light, after all, is
image, because every point of the object sends Jenny's work on vibration,4 the principle of simply the result of causing the molecules of a
light to every point on the hologram. The interference seems very general. A simpler gas or crystal to behave in a more organized
smaller the fragments, the poorer the definition. example of interference than holography is manner.
3. Either the positive or the negative versions moire patterning. Moire patterns are des- Everyone assents nowadays to the importance
of a hologram will generate the identical 3-D cribed by Oster and Nishijima5 as simple and ubiquity of 'communication'. But one
image; there is no reversal of dark and light analogues of complex mathematical pheno- can't begin to understand how messages are
as in ordinary photography. mena. Large alterations in patterning can be transmitted and patterns recognized, unless
4. With today's techniques, the images pro- produced by amplification from a very slight one accepts the importance of interference (a
duced are speckled and coarse-grained. This shift of phase or alignment. The rhythmic word which in ordinary English has un-
does not show up in photographs of holo- patterning of watered silk or moire antique is fortunate overtones of destructiveness). The
grams, which are of course imperfect illustra- due to the superimposition by pressure of kind of imagery in the Lashley quotation
tions of the actual effect. slightly misaligned parallel weaves. The role above recalls both music and the rhythmic
5. Movement of an object during recording of interference patterning in the work of such aspects of literature. If a new aesthetic is
causes not the blurring of ordinary photo- artists as Vasarely, Riley, Soto (to name but emerging today, it will surely incorporate a
graphy, but a loss of image brightness. a few) is well known. fine sensitivity to wave-patterns and inter-
Explanations of all these properties, and It may be helpful to consider holography in ferences. We talk already of being on the
several others, will be found in textbooks or in its most general terms. It is the means where- same 'wavelength' as someone, of liking the
the sources which I list in a footnote.' by patterns or messages generated by events `tempo' of a metropolis, or of absorbing the
Holograms designed to illustrate these special in a particular area of space and time inter- `rhythms' of the countryside, as if our
properties often depict cut-glass objects, act to generate new patterns, which represent universe were an immense hologram of inter-
where glints of light appear and disappear as the way in which the separate events inter- fering wavefronts. The fact is that these verbal
the viewer moves from side to side, or lenses, relate. These cross-correlations are read out usages are probably accurate, but we lack at
which cause objects behind them to enlarge when we inject into them a reference wave- present both the perceptual tools to justify
or contract as the viewer moves forward and length, which has the property of imposing an them, and the vocabulary to describe subtle
away. Margaret Benyon is an artist and she ordered set-structure. interrelations and life-frequencies. Miss Ben-
avoids the didactic or the conventionally Several writers on neurology draw on the yon's holograms are as expressive of the cul-
aesthetic. She builds constructions of her own holographic analogy. K. S. Lashley has ture that is upon us as were eighteenth-
design for holographic recording— construc- postulated that the transmission of messages century automata of a simpler and more
tions which often, as in the illustration, in- within the richly connected cerebral cortex static ecological order. q
corporate interference patterns themselves. takes place by the superimposition of fluctu- JONATHAN BENTHALL
It may be objected to Benyon's work, 'Why ating patterns, resulting from current stimu-
make a hologram of a sculpture? Why not lation, against a substratum of persistent
just exhibit the sculpture?' It is too early to rhythms. Especially poetic is his illustration 1 Sources:
make any evaluation of her work, as there is of the brain's nervous action as the surface of Scientific American, September 1968, issue on Light.
`Holography', B. J. Thompson and G. B. Parrent Jr.,
very little to compare it with—though Jerry a lake (written in 1951 before laser holo- Science Journal , January 1967.
Pethick2 and one or two others are working in graphy was invented) : `Fundamentals of Holography', Winston E. Kock,
this field—and no defence is needed for the `The prevailing breeze carries small ripples Laser Focus, February 1969.
sensitive and dedicated exploration of a new, in its direction, the basic polarity of the I am also grateful to Mr Gordon Hyde and Mr Adrian
exacting medium. But the criticism men- system. Varying gusts set up crossing sys- Nutbeem for help with the latter part of this article.
2 'On sculpture and laser holography: a statement',
tioned is unfair to Benyon since her chief tems of waves, which do not destroy the first Jerry Pethick, artscanada, December 1968.
interest is in 'phenomena that are peculiar to ripples, but modify their form, a second `Acoustical Holography', Alexander F. Metherell,
the holographic medium'. For instance, she level in the system of space co-ordinates. A Scientific American, October 1969. The interaction of
has constructed a kind of baffle consisting of tossing log with its own period of submer- sound with solids and liquids is different from that of
moving parts which don't record but form a sion sends out periodic bursts of ripples, a light. 'Sound can travel a considerable distance through
dense, homogeneous matter and lose little energy, and
black area that you can see behind. In another temporal rhythm. The bow wave of a
yet it will lose a significant amount of energy when it
piece she has recorded heat waves' trails. speeding boat momentarily sweeps over the passes through an interface. . . . Therefore sound can
It is the 3-D properties of holography that surface, seems to obliterate the smaller be singularly effective in medical diagnosis, in non-
have attracted most attention, and there has waves yet leaves them unchanged by its destructive testing and in seeing underwater and under-
been talk of using large holographic pro- passing, the transient effect of a strong ground because it is mostly the discontinuities of
internal organs, tumors, flaws, submerged objects or
jections in an architectural, or theatrical con- stimulus. Wave motion is not an adequate
subterranean strata, rather than the bulk matter, that
text. These are indeed interesting prospects, analogy because the medium which con- is of interest to the observer'.
but unfortunately so much has been written veys the waves is uniform, whereas the nerve 4 'Hans Jenny and cymatics', Studio International,
about them that some people are disappointed cells have their individual characteristics November 1969.
by the modesty of existing holographic tech- of transmission which at every point may `Moire Patterns', G. Oster and Y. Nishijima,
Scientific American, May 1963.
niques. In fact, the 3-D properties of holo- alter the character of the transmitted
6 K. S. Lashley, Perception and Action (ed. Pribram,
graphy are a by-product of a far more funda- pattern.' 6 Penguin 1969), p. 537f.
mental principle, that of interference. It is K. H. Pribram writing in 1966 refers ex- 7 K. H. Pribram, ibid., p. 254ff.