DEVELOPING AND PRINTING THE PICTURES
The history of the cinematograph impresses upon us at every turn the
necessity which experimenters were under of devising special facilities
and improved apparatus in all of the numerous fields that impinged upon
their work. They were obliged to break ground in every direction. For
instance, besides securing the right kind of film, they had also to
find the best means of developing it. A thin, narrow ribbon of pictures
40 feet in length is a vastly different thing to handle from a rigid
glass plate. Its flexibility presented many perplexing obstacles which
had to be overcome. Those who used the old roll film with the snap-shot
hand-camera of the early days, can relate pathetic and humorous
stories of the trials and tribulations they suffered in passing
the awkward length of film through the developing and other baths.
When it was unwound from the roller preparatory to immersion in the
developing solution, it persisted in buckling and twisting into strange
contortions. Development was carried out in an uneven or patchwork
manner, some parts of the film being fully developed before others had
betrayed the slightest sign of yielding the latent image.
The plight of the animated photographer was even more unenviable;
the handling of sensitised celluloid about as thick as a substantial
wooden shaving, was infinitely more exasperating than that used in
the ordinary hand camera, for the latter was wider, thicker, and far
shorter.
The developing methods at first advocated were of the crudest nature
possible. Messrs. Lumière tried to assist the tyro by comprehensive
explanation of a very simple way to carry out the task. They suggested
suspending the coil of exposed film upon a rod slipped through the
centre of the bobbin to form a kind of spindle, upon which the coiled
film was free to revolve over the bath. The operator was then told to
unwind the coil very rapidly by hand, passing it into the bath between
the fingers, which acted as a guide.
It appeared an absurdly simple operation, but without considerable
practice it defied success. One had to be extremely careful not to
damage the delicate sensitised emulsion of the film while uncoiling it;
that no greasy matter, such as perspiration from the fingers, might
come into contact with the gelatine surface; and no bubbles must be
produced while feeding the slippery strip into the bath. Mr. Robert
Paul experienced these troubles, and displayed considerable ingenuity
in the evolution of special means to avoid them. The efficiency of his
method is proven by the fact that in the main it is practised to this
day.
[Illustration: _By courtesy of Messrs. Butcher & Sons, Ltd._
FIG. 7.--HOW THE FILM IS WOUND UPON THE WOODEN FRAME FOR DEVELOPING.]
His solution of the problem was simple, safe, and satisfactory from
every point of view. He took a light, square wooden frame, similar to
that in Fig. 7, which rested loosely upon two uprights in such a way
that it could revolve. The free end of the film was fixed to one side
of the frame, and the film was then passed from one side to the other,
as if being wound upon a wheel, as it was uncoiled from the spool, the
inner end of the film being likewise secured to the frame. This rack
was dipped first into a vertical tank to soak the film, and then was
placed in a flat tank or trough to be developed in the same way as an
ordinary glass plate. By this means every part of the exposed surface
was developed equally. Development carried to the requisite degree, the
frame was withdrawn, washed, and finally immersed in the fixing tank,
which was of the same horizontal design. When the image was fixed it
was placed in another tank and received a thorough washing, to remove
all traces of the fixing solution, as in the ordinary developing
process. This task completed, the film was uncoiled from the flat
rack to be re-coiled upon a wooden drum, which was suspended from the
ceiling in the drying chamber, until the film was dry and hard.
As may be supposed, different factories practise different methods
of carrying out this operation. Nowadays a film may be as much as
300 or 400 feet in length, and consequently special methods have to
be employed. I have been in some establishments where development is
carried out upon an extensive scale, in which the films, as withdrawn
from the camera film box, are wound at once upon a large wooden
reel, seven feet or so in length, suspended upon brackets above the
developing bath. When the drum has received its full length of film
it is lowered into a deep tank containing the desired solution, and
there kept revolving slowly and steadily until the treatment has been
completed. Then the reel is withdrawn by two men and lowered into the
next bath; and so on until at last the reel finds its way into the
drying room, where the film is uncoiled from the developing drum and
re-wound upon the drying reel. The disadvantage of this process is that
two men are required to handle the reel, whereas, when a frame is used,
one pair of hands is sufficient.
[Illustration: THE DEVELOPING ROOM AT THE PATHÉ WORKS.
The films are wound upon wooden frames and immersed in large tanks
containing the various solutions.]
The developing and printing rooms in a large film-picture factory
are highly interesting hives of activity. Large troughs and tanks
containing the various solutions are on every hand, together with
adequate supplies of running water. Everything, of course, is carried
out in semi-darkness, the only light available being that emitted from
ruby lamps. The fixing solution after it has served its purpose is
not thrown away, but is subjected to a chemical treatment to recover
the bromide of silver which the hyposulphite of soda has dissolved
from the sensitised emulsion on the film. The silver in suspension is
precipitated by chemical action in a thick sediment. In large works
this recovery process is profitable, several pounds of this metallic
silver being secured every week.
[Illustration: THE DRYING ROOM AT THE PATHÉ WORKS.
This illustration shows the wooden frames upon which the lengths of
film are wound and the overhead racks from which they are suspended.]
The solution employed for development is either a combination of
hydroquinone and metol, or a bath of rodinal, developing agents which
are familiar to the amateur photographer, while the fixing bath is a
solution of hyposulphite of soda. The developing formula is modified
by various firms as a result of individual investigation. The drying
operation is one that has to be carried out very carefully; the
temperature of the chamber must be evenly maintained, and the air which
is circulated through the room must be filtered before admission, in
order to arrest all particles of dust which otherwise might settle upon
the gelatine surface and wreak appreciable damage.
In the early days the fickle character of the film was a serious
difficulty. If it were dried too rapidly it evinced a tendency to
curl, and severe shrinkage often ensued. To guard against this trouble
the film was glycerined before being dried, by being passed through a
bath containing a solution of glycerine and alcohol. The improvements
effected in the manufacture of the film, however, have enabled this
subsidiary treatment to be dispensed with. In cases where a topical
film must be rushed out quickly to catch the public in the height of
its interest, however, drying is accelerated by subjecting the film to
a bath of alcohol in some form or other.
Although a spool of film, measuring perhaps 300 feet in length, is
handed over for development, possibly that 300 feet carries two, four,
or more exposures, _i.e._, different sections were exposed at different
times, on different days, or under different conditions of light, &c.
The camera operator has indicated the end of each exposure by means of
the camera punch. When the developing operator receives the spool, he
first searches for such marks as he uncoils the film, and the latter
is severed at those points, and each exposure is developed separately.
When the developing process is completed, therefore, the film relating
to one subject is in a fragmentary condition. These odds and ends
have to be sorted out, all useless parts cut away, and then arranged
in sequence and joined together to form a continuous band containing,
in the ordinary case, the whole subject. If the series of pictures
runs into two or three thousand feet, the aggregate will be divided
into 1,000 feet sections, which is the approximate capacity of the
spool mounted on the projector. The sections are united by means of a
transparent cement, known as amyl-acetate.
When the negative is dry and the gelatine surface has hardened enough
to permit the sections to be handled and joined together, the next
stage is taken in hand. This is printing the positive. Obviously a
printing frame, such as the amateur uses for printing from a single
glass plate, is quite out of the question with a negative several
hundred feet in length. Invention born of necessity has met this
question in a novel manner, and the printing process is one of the
most interesting phases in the preparation of a picture. Considerable
mechanical ingenuity has been displayed, and various types of printing
machines produced; but for the purposes of explaining the subject most
lucidly and comprehensively two typical machines will suffice. Before
printing, however, the raw film or stock intended for the purposes of
the positive or transparency must be perforated, an operation which is
similar to that followed in perforating the negative film.
Printing is carried out by contact; that is to say, the sensitised
surface of the positive film is pressed tightly against the emulsion
side of the negative film at the instant the exposure is made. One
image is printed at one time. The two films are given an intermittent
action, the consecutive images on the negative film and the
corresponding sections of sensitised surfaces on the positive film
being brought before the illuminant during the brief period that the
light is cut off from the printing box by the passage of the shutter.
[Illustration: FIG. 8--FRONT AND SIDE VIEWS OF NEWMAN-SINCLAIR PRINTING
APPARATUS.]
In the Newman-Sinclair apparatus, Fig. 8, the negative film is wound
upon spool 1, while the positive film is carried on spool 2, both being
supported upon the projecting bracket 3. The negative passes over the
guide roller _A_, and descends with the positive film to the toothed
sprocket 4. At this point the two films are brought together with the
gelatine surfaces inside, while the teeth of the sprocket mesh with the
perforations in each. The two films pass from this sprocket, form a
loop, and together enter the gate, which clamps them tightly and flatly
together, with their respective perforations exactly coinciding.
At the point where the two films come opposite the aperture through
which passes the light from the lamp, there is a mask, by which the
position of the picture relative to the exposure hole is corrected.
The mask also determines the shape of the positive picture. It may
be rectangular, oval, circular, or have rounded corners as desired.
Immediately behind the film, in line with the exposing aperture, is a
red screen, over which a shutter slides. When this shutter is opened,
the operator can see the negative image through the positive film,
and thus can ascertain that the position of the picture is correct in
relation to the exposure aperture, and also that the perforations on
the two films are in synchrony. The light by which the exposure is made
is contained in a light-tight box, or may be placed on the outside of
the wall of the printing room, an aperture being cut in the partition
to admit the light to the printing apparatus, which is screwed to the
wall. Between the light and the film there is a revolving shutter, as
in the camera, which cuts off the light intermittently, enabling the
succeeding negative image and area of positive film to be brought into
position before the exposure orifice.
[Illustration: A ROW OF PRINTING MACHINES IN THE ROME WORKS OF THE
CINES COMPANY.
This establishment is able to print 100,000 feet of film per day.]
The film is drawn through the machine by a pair of fingers or claws
which engage with the perforations of the two films and pull them
downwards together. As the pictures are printed, the negative and
positive films pass into boxes or other suitable receptacles to be
re-wound on their respective spools. The machine can be operated either
by hand or power according to the requirements of the establishment.
As the sensitised surface of the positive film is slower than that of
the negative, printing is carried out at a reduced speed, the average
recommended with this apparatus being about five pictures per second.
Another printing machine has been recently produced which is regarded
as the simplest, most mechanically perfect, most compact, and
self-contained apparatus yet devised for this work, and which compels
attention as much from its efficiency as from the point of view of
mechanical excellence. This is the Williamson printer. It is a complete
unit, and can be moved from place to place with facility.
[Illustration: THE WILLIAMSON PRINTING MACHINE.
For making the positive films.--_For explanation see page 82._]
It comprises a large rectangular box or cabinet, standing on one end.
The front face carries the printing mechanism, while the interior,
divided into two compartments, contains the driving mechanism and the
illuminating agency for printing. The apparatus is so designed that
after printing the films are wound upon separate spools at once, thus
saving time, and dispensing with the necessity of a box or basket to
gather the loose films, which is both a dangerous and an unsatisfactory
process, inasmuch as the films are liable to become damaged by curling
and cracking, and through the surfaces rubbing against one another.
The negative film is placed upon the spool _A_ immediately below
which is the positive film spool _B_. The sensitised surfaces of the
two films face one another, and the two are brought together as they
pass under the grip rollers and over the toothed sprocket _C_, where
the teeth mesh with the perforations in the respective films. Issuing
from this sprocket a loop is formed, and then the films enter the gate
_D_ over the printing aperture. This gate is side-hinged, and when
closed it presses evenly upon the whole surface of the films under
exposure, ensuring a perfect even contact. There is a small red screen
_E_, which, when released by means of a small lever, drops down, thus
enabling the negative to be examined without danger of the positive
film being fogged in the operation. By this means the printer can
satisfy himself that the picture is central to the exposure hole.
As the picture is printed, a simple claw device _F_, resembling two
hooked fingers, engages with the perforations in the two films and
draws them downwards. This claw device is of very simple construction,
working on a cam, so that when the film has moved downwards the proper
distance--sufficient to bring the succeeding picture and its area of
unexposed positive film before the printing aperture--the fingers
disengage themselves from the films, rise, and move upwards to drop
into other perforations and repeat the operation.
As the film descends, it forms a loop, and passes under a double
smooth-faced roller and a toothed sprocket _G_, at which point the two
films part company, the positive to be wound upon the bobbin _H_, while
the negative film is wound upon the lower bobbin _I_. These lower
spools are driven by belt and pulleys from a bevel gear wheel, which
carries a spindle actuating the claw giving the intermittent movement
to the films, and which by means of another spindle rotates the upper
and lower sprockets _C_ and _G_ so that the loops above and below the
gate remain constant. By this arrangement no pull or strain is imposed
upon the films by the sprockets, which act merely as guides and not
tractive devices.
The compartment _J_ is lined with asbestos, and contains the illuminant
by means of which the printing is done. An electric lamp of 50
candle-power, having a filament in the form of a grid, is placed
directly opposite the window through which the exposures are made. This
lamp is mounted upon a slide controlled by a lever on a quadrant on
the face of the machine, by means of which it may be moved as required
from 2 inches to 10 inches from the printing window. The power of the
light may be varied according to the density of the negative by means
of a controller, which increases or decreases its intensity in much
the same way as a gas jet can be turned up or down, it being possible
to secure six variations in light intensity ranging between 16 and 50
candle-power. When the door of the chamber is closed the compartment is
perfectly light-tight, though ample ventilation is secured.
The lower compartment _K_ carries the electric motor by means of
which the apparatus is driven, and the speed of printing is altered
at will by means of a controller. The motor is of 1/12 horse-power,
and six direct speeds can be obtained. The drive is communicated to
the mechanism through a system of cone pulleys, which enable three
speeds to be obtained; and as each of these three speeds can be given
one of the six speeds of the motor by means of the regulating switch
or controller, the apparatus can be driven at eighteen different
speeds, according to requirements. Wide range of action, combined with
simplicity of control, characterise this apparatus. The printing speed
varies according to the density of negative and the intensity of the
light, but the average speed in printing from a normal negative is
about 500 exposures of pictures per minute.
The positive film, after being exposed, is developed by a method
similar to that used for the negative. Both these developing processes
demand considerable skill and experience in order to ensure the best
possible results. An accomplished developer, like his colleague
working with glass plates, can rectify many deficiencies arising
during exposure. The camera operator often has to work under the most
adverse conditions concerning light, and it is the task of the man in
the dark room to obtain the utmost from a poor negative. By care and
attention, combined with experience and knowledge, he will be able
to improve, make up for under-exposure, and mitigate the evils due
to over-exposure. It will be realised that development is the most
critical stage in the whole operation, for upon the manner in which
it is carried out much of the excellence and merit of the projected
picture depends.
The fact that the cinematograph camera is being regarded more and
more as an indispensable unit in the impedimenta for travelling and
exploring expeditions has resulted in attention being devoted to the
perfection of a small portable developing outfit to enable films to
be developed at once, instead of sending them home for treatment, as
hitherto has been the case. The “N.S.” developing apparatus is an
excellent appliance of this character. It has been taken by Captain
Scott, R.N., upon his Antarctic expedition, and forms part of the
photographic outfit carried by Mr. Cherry Kearton upon his travels.
The developing apparatus consists of a rotating cylinder and two or
more semi-circular troughs. The film is wound spirally upon the drum,
being held in position by means of wire staples, and the apparatus is
so designed that the drum with its film can be moved from one trough
to the other by the simple movement of a lever. The design of the
apparatus ensures economy in the quantity of developer required. Three
pints of solution are sufficient to treat 75 feet of film, and the bath
can be thrown away when work is finished or bottled for further use.
After washing, the film is wound upon a collapsible drum, which folds
into a small space when not in use. The outfit is made of pine, with
waterproofed joints, the whole of the woodwork being treated with
paraffin wax to render it impervious to the action of chemicals and
moisture. When packed, the apparatus, capable of dealing with 50 feet
of film, measures 3½ feet in length, by 26 inches wide, and 18 inches
deep. The outer packing constitutes the support for the apparatus when
in operation.
Waste is absolutely unavoidable in the cinematograph industry, and
no matter how carefully operations may be conducted, it is bound to
assume impressive proportions. In a travelling expedition the operator
records pictures of what he deems to be sufficiently interesting from
various points of view--scenic, ethnographic, historical, or merely
anecdotal and humorous. When the films are developed and a trial
positive is struck for projection before the powers that be, to receive
official approbation and sanction to enter the market, the critics in
the private projecting room sometimes fail to see eye to eye with the
cinematographer, and deem this and that to be lacking in the essentials
which render a film attractive to the public. Accordingly, these
sections are eliminated. From 300 to 3,000 feet may be destroyed in
this manner.
The waste is still greater in the filming of picture plays. Sometimes a
scene, occupying 100 or 150 feet of film, will have to be photographed
three or four times. I once saw a scene, taking 200 feet of film,
recorded six times before it gave satisfaction. It was a picture
involving the movements of a large crowd, and in five instances
something went wrong at one point or another, despite the fact that
rehearsals had been prosecuted with such energy and persistence that
at last everything appeared to move with the precision of the wheels
of a watch. A thousand feet of film were spoiled in this particular
case, which, at an average of 1½_d._ (three cents) a foot, represented
a waste of £6 or $30 in film alone. Yet this is by no means an isolated
instance; the proportion often approximates 20 per cent.; that is to
say, 200 feet out of 1,000 feet are useless. The bigger the production
being recorded, the heavier the waste in this direction.
When the positives have been dried and hardened sufficiently to enable
them to be handled, they are sent to a room where the different
sections are identified and allotted to their positions in the subjects
to which they belong. The sections are joined together, the lengths
of film bearing the explanatory sub-titles are inserted in the proper
places, and the whole subject, after a final examination, is wound upon
a spool ready for the market. The examination of the films is carried
out rigorously, those suffering from the slightest blemish or coming
below the firm’s standard being discarded.
It has been seen from the foregoing that the preparations for
developing and printing are somewhat elaborate, and demand expensive
apparatus in order to insure the most satisfactory results. These
considerations react against the amateur cinematographer. But should
one fall a victim to the fascinating glamour of cinematography, one
need not apprehend difficulties in connection with developing and
printing. There is no necessity to acquire perforators, to establish
a complete developing room, or to invest in a printing machine. The
majority of cinematograph manufacturing establishments undertake to
develop negatives, and to supply positive prints ready for projection
at a nominal figure. It is far better to entrust the work to a skilled
staff, who can be trusted to handle the film successfully, than to
attempt to wrestle with unknown difficulties with a serpent-like film
200 feet long, in the murky gloom of the dark room.