A record, if it is to be useful to science, must be continuously
extended, it must be stored, and above all it must be consulted.
Today we make the record conventionally by writing and photography,
followed by printing; but we also record on film, on wax disks,
and on magnetic wires. Even if utterly new recording procedures
do not appear, these present ones are certainly in the process
of modification and extension.
Certainly progress in photography is not going to stop. Faster
material and lenses, more automatic cameras, finer-grained sensitive
compounds to allow an extension of the minicamera idea, are all
imminent. Let us project this trend ahead to a logical, if not
inevitable, outcome. The camera hound of the future wears on
his forehead a lump a little larger than a walnut. It takes pictures
3 millimeters square, later to be projected or enlarged, which
after all involves only a factor of 10 beyond present practice.
The lens is of universal focus, down to any distance accommodated
by the unaided eye, simply because it is of short focal length.
There is a built-in photocell on the walnut such as we now have
on at least one camera, which automatically adjusts exposure
for a wide range of illumination. There is film in the walnut
for a hundred exposures, and the spring for operating its shutter
and shifting its film is wound once for all when the film clip
is inserted. It produces its result in full color. It may well
be stereoscopic, and record with spaced glass eyes, for striking
improvements in stereoscopic technique are just around the corner.
The cord which trips its shutter may reach down a man's sleeve
within easy reach of his fingers. A quick squeeze, and the picture
is taken. On a pair of ordinary glasses is a square of fine lines
near the top of one lens, where it is out of the way of ordinary
vision. When an object appears in that square, it is lined up
for its picture. As the scientist of the future moves about the
laboratory or the field, every time he looks at something worthy
of the record, he trips the shutter and in it goes, without even
an audible click. Is this all fantastic? The only fantastic thing
about it is the idea of making as many pictures as would result
from its use.
Will there be dry photography? It is already here in two forms.
When Brady made his Civil War pictures, the plate had to be wet
at the time of exposure. Now it has to be wet during development
instead. In the future perhaps it need not be wetted at all.
There have long been films impregnated with diazo
dyes which form a picture without development, so that it is
already there as soon as the camera has been operated. An exposure
to ammonia gas destroys the unexposed dye, and the picture can
then be taken out into the light and examined. The process is
now slow, but someone may speed it up, and it has no grain difficulties
such as now keep photographic researchers busy. Often it would
be advantageous to be able to snap the camera and to look at
the picture immediately.
Another process now in use is also slow, and more or less
clumsy. For fifty years impregnated papers have been used which
turn dark at every point where an electrical contact touches
them, by reason of the chemical change thus produced in an iodine
compound included in the paper. They have been used to make records,
for a pointer moving across them can leave a trail behind. If
the electrical potential on the pointer is varied as it moves,
the line becomes light or dark in accordance with the potential.
This scheme is now used in facsimile transmission. The pointer
draws a set of closely spaced lines across the paper one after
another. As it moves, its potential is varied in accordance with
a varying current received over wires from a distant station,
where these variations are produced by a photocell which is similarly
scanning a picture. At every instant the darkness of the line
being drawn is made equal to the darkness of the point on the
picture being observed by the photocell. Thus, when the whole
picture has been covered, a replica appears at the receiving
A scene itself can be just as well looked over line by line
by the photocell in this way as can a photograph of the scene.
This whole apparatus constitutes a camera, with the added feature,
which can be dispensed with if desired, of making its picture
at a distance. It is slow, and the picture is poor in detail.
Still, it does give another process of dry photography, in which
the picture is finished as soon as it is taken.
It would be a brave man who could predict that such a process
will always remain clumsy, slow, and faulty in detail. Television
equipment today transmits sixteen reasonably good images a second,
and it involves only two essential differences from the process
described above. For one, the record is made by a moving beam
of electrons rather than a moving pointer, for the reason that
an electron beam can sweep across the picture very rapidly indeed.
The other difference involves merely the use of a screen which
glows momentarily when the electrons hit, rather than a chemically
treated paper or film which is permanently altered. This speed
is necessary in television, for motion pictures rather than stills
are the object.
Use chemically treated film in place of the glowing screen,
allow the apparatus to transmit one picture rather than a succession,
and a rapid camera for dry photography results. The treated film
needs to be far faster in action than present examples, but it
probably could be. More serious is the objection that this scheme
would involve putting the film inside a vacuum chamber, for electron
beams behave normally only in such a rarefied environment. This
difficulty could be avoided by allowing the electron beam to
play on one side of a partition, and by pressing the film against
the other side, if this partition were such as to allow the electrons
to go through perpendicular to its surface, and to prevent them
from spreading out sideways. Such partitions, in crude form,
could certainly be constructed, and they will hardly hold up
the general development.
Like dry photography, microphotography still has a long way
to go. The basic scheme of reducing the size of the record, and
examining it by projection rather than directly, has possibilities
too great to be ignored. The combination of optical projection
and photographic reduction is already producing some results
in microfilm for scholarly purposes, and the potentialities are
highly suggestive. Today, with microfilm, reductions by a linear
factor of 20 can be employed and still produce full clarity when
the material is re-enlarged for examination. The limits are set
by the graininess of the film, the excellence of the optical
system, and the efficiency of the light sources employed. All
of these are rapidly improving.
Assume a linear ratio of 100 for future use. Consider film
of the same thickness as paper, although thinner film will certainly
be usable. Even under these conditions there would be a total
factor of 10,000 between the bulk of the ordinary record on books,
and its microfilm replica. The Encyclopoedia
Britannica could be reduced to the volume of a matchbox.
A library of a million volumes could be compressed into one end
of a desk. If the human race has produced since the invention
of movable type a total record, in the form of magazines, newspapers,
books, tracts, advertising blurbs, correspondence, having a volume
corresponding to a billion books, the whole affair, assembled
and compressed, could be lugged off in a moving van. Mere compression,
of course, is not enough; one needs not only to make and store
a record but also to be able to consult it, and this aspect of
the matter comes later. Even the modern great library is not
generally consulted; it is nibbled by a few.
Compression is important, however, when it comes to costs.
The material for the microfilm Britannica would cost a
nickel, and it could be mailed anywhere for a cent. What would
it cost to print a million copies? To print a sheet of newspaper,
in a large edition, costs a small fraction of a cent. The entire
material of the Britannica in reduced microfilm form would
go on a sheet eight and one-half by eleven inches. Once it is
available, with the photographic reproduction methods of the
future, duplicates in large quantities could probably be turned
out for a cent apiece beyond the cost of materials. The preparation
of the original copy? That introduces the next aspect of the