Page 27 - Studio International - March 1967

this light from its surface in all directions. Some of the
reflected light is allowed to fall on a photographic plate,
which is also illuminated directly by the laser beam. The
photograph then records the interaction between the
direct laser light, which is very orderly, and the reflected
light, which has been made disorderly in ways which
correspond exactly to the surface from which it was
reflected. All we have to do now with this photograph is
to cancel out the direct laser light and we should be left
with a record of the light reflected from the object. It is
not very difficult to do this: it corresponds to laying on
the square of parallel lines in figure 2 another comple-
mentary square in which white has been replaced by
black and vice versa.
This may at first sight seem a long way round to get an
ordinary photograph. But in fact the photograph is by no
means ordinary. The light reflected by the object was
brought through any lens to a focus before being recorded.
It has not been recorded in fact as though we were look-
ing at the object only through one eye placed at a definite
spot, but we have captured all the light reflected by the
object on to the whole area of the photographic plate,
which can be quite large. This means, in the first place,
that any part of the photographic plate has got the whole
image on it. Even if we cut the plate up into halves or
quarters, we can reconstruct the entire scene although, if
the fragment of the plate is too small, the amount of
detail becomes considerably reduced. Another and per-
haps even more remarkable property is that, if the photo-
graph is tilted slightly while being printed, we get a
series of images of the object as though it were seen first
from one edge of the plate, then through the middle, and
finally from the other edge. With a fairly large plate, we
are coming quite near to having captured both the full
face and profile of views at once. In the 'wave front'
photographs we have, in fact, recorded much more infor-
mation about the object than is included in any photo-
graph or drawing made from only one position. Now
what does our image, so rich in content, actually look
like ? Figure 5 shows an enlarged part of such a photo-
graph, or 'hologram' as it is called. It is really, as we
have said, an extremely complicated moire pattern and
it has the characteristic modern all-overness, which to
eyes not yet attuned to the modern idiom often seems
merely chaotic and meaningless. This is a case in which
such an all-over pattern is certainly by no means
meaningless—contains, in fact, 'more meaning than a
conventional photograph'. In its unfocused and appear-

Abode left, fig. 4
The hologram from which the prints in Figure 3 were made. The
left hand two in Figure 3 are made by printing from different
small areas from the complete hologram. In order to record a larger
change in viewpoint a hologram negative of greater dimensions
would have to be used. The right hand two photos in Figure 3 were
made by printing from larger or smaller areas taken from the
same region of the hologram

Left, fig. 5
An enlarged picture of a portion of a hologram to show the real
character of the surface pattern