THE BARNET
BOOK OF
PHOTOGRAPHY.
THE BARNET
BOOK OF
PHOTOGRAPHY.
A COLLECTION OF PRACTICAL ARTICLES
BY
CAPT. W. DE W. ABNEY, C.B., F.R.S., ETC.
CHARLES H. BOTHAMLEY, F.C.S., F.I.C.
CHAPMAN JONES, F.C.S., F.I.C.
HAROLD BAKER
A. HORSLEY HINTON
JOHN H. AVERY
W. THOMAS
ANDREW PRINGLE
JOHN A. HODGES, F.R.P.S.
REV. F. C. LAMBERT, M.A.
W. ETHELBERT HENRY, C.E.
JAMES PACKHAM, F.R.P.S.
THO'S. S. SKELTON
[Illustration]
THIRD EDITION.
Published by
ELLIOTT & SON, BARNET, HERTS.
PERCY LUND, HUMPHRIES & CO., LTD.,
3, AMEN CORNER, LONDON, E.C.
1898.
[Illustration]
CONTENTS OF
THE BOOK.
PAGE.
ALPINE PHOTOGRAPHY. _W. de W. Abney, C.B., F.R.S._ 9
NEGATIVE MAKING. _C. H. Bothamley, F.C.S., F.I.C._ 23
LENSES. _Chapman Jones, F.C.S., F.I.C._ 57
PORTRAITURE. _Harold Baker_ 77
PICTORIAL PHOTOGRAPHY. _A. Horsley Hinton_ 87
ARCHITECTURAL PHOTOGRAPHY. _John H. Avery_ 117
THE HAND CAMERA AND ITS USE. _W. Thomas_ 131
LANTERN SLIDES. _Andrew Pringle_ 141
HOW TO MAKE ENLARGEMENTS. _John A. Hodges, F.R.P.S._ 155
P.O.P. _Rev. F. C. Lambert, M.A._ 177
PLATINOTYPE PRINTING. _A. Horsley Hinton_ 197
CONTACT PRINTING ON BROMIDE PAPER. _W. Ethelbert Henry, C.E._ 225
THE GUM-BICHROMATE PROCESS. _Jas. Packham, F.R.P.S._ 241
AN INTRODUCTION TO CARBON PRINTING FOR BEGINNERS 253
THE CARBON PROCESS. _Thomas S. Skelton_ 261
ILLUSTRATIONS.
HOMEWARDS. KARL GREGER 16
AMONG THE ALPS. W. DE W. ABNEY 24
WINTER TIME ON THE ALPS. W. DE W. ABNEY 40
MELTON MEADOWS. A. HORSLEY HINTON 72
MISS LILY HANBURY--A PORTRAIT. HAROLD BAKER 88
GATHER THE ROSES WHILE YE MAY. ALEX. KEIGHLEY 120
BIRCH AND BRACKEN. W. THOMAS 136
DRIFTING STORM CLOUDS. W. THOMAS 168
STREONSALCH. W. J. WARREN 200
CUPBOARD LOVE. T. LEE SYMS 232
AT THE FOUNTAIN. J. W. WADE 264
PREFACE.
[Illustration: THE BARNET BOOK OF PHOTOGRAPHY.]
_The purpose of this book is to place in the hands of every
Photographer instructive articles on essential processes and
manipulations, by eminent writers who have given such subjects their
especial study, and who have borne in mind that whilst the
experienced Amateur and the Professional may each find much to learn
from a comparatively elementary description of methods and means, it
is the Beginner who stands in greatest need of help._
_In the mind of every photographer the name of Barnet is inseparable
from a great Photographic Industry, and now it is intended that the
name shall be associated with a good and useful book, which is
called the_ BARNET BOOK OF PHOTOGRAPHY, _and it is left to the
reader to say if the fulfilment of its purpose and the manner of its
doing are such as to justify its existence._
_To all who are interested in photography, who love it for itself
and for its productions, and who desire to improve their own
practice of its many processes and applications, this Book is
respectfully dedicated._
_Barnet, Herts._
_April, 1898._
_ELLIOTT & SON._
[Illustration: COPYRIGHT. NEGATIVE BY W. L. F. WASTELL. A FAMOUS
PIKE STREAM. Contact Print on BARNET PLATINO-MATT BROMIDE PAPER.]
_Alpine Photography._
[Illustration]
Writing in London on a day in winter with a murky sky and sloshy
streets, the title of Alpine Photography is verily refreshing. It
brings back days of sunlight and joyous experiment, and as we write
the soul stirring scenery is before us called up by photographs
taken under varying conditions of comfort and discomfort. That there
is something different in Alpine photography to photography in our
own country, we are bound to believe, since a special article is
demanded for it.
The first question invariably asked is as to the nature of the outfit
required. We should here like to divide our reply into two divisions.
The one concerning the mountaineer, and the other the ordinary
tourist. For the former we have no doubt in our minds that a hand
camera to take 1/4 plate or 5 × 4 pictures is the most convenient
form of camera to take. It is not our business to advertise any
person's wares and we shall content ourselves by saying that
personally we prefer a camera which has separate slides and does not
possess a magazine, more particularly when glass plates are to be
used, though a form of Kodak is not to be despised. But perhaps we
are prejudiced in favour of glass plates, for they are simple to
manipulate and have no cockles nor other drawbacks which the careless
photographer may have to encounter. Probably the most useful lens to
employ is a doublet of which the focal length is about a quarter more
than the width of the plate, since it includes a fair angle and the
margins of the photographs are not likely to be markedly different in
general density to the centre, as is the case when wide-angle lenses
are employed. In England a lens which will cover with a large stop,
say _f_/8, is a desideratum, but in the Alps it is very rarely that
such a large ratio of aperture to focal length is required. As a rule
for ordinary plates a lens has to be stopped down to _f_/16 to give a
negative in say 1/50th of a second. Nevertheless where orthochromatic
plates are to be employed it is very necessary to have a lens which
will cover a plate satisfactorily with _f_/8 in order to use a colour
screen for producing orthochromatic effects, since the loss of
photographic light caused by the screen can only be compensated for
by such an aperture even when the shutter is slowed down. The reader
is therefore recommended on the whole to furnish himself with one of
the modern lenses which work at _f_/8, though he must remember that
the larger the aperture employed the more the margins and centre of
the picture will suffer from unequal exposure. With some hand cameras
there is a means of attachment to a stand, but a stand on a mountain
is difficult to use and moreover has on more than one occasion been
proved dangerous to carry. The mountaineer if he desires to give a
time--and not an instantaneous--exposure on his excursion, would do
well to have a small clip ready to attach to the head of his ice axe.
The axe will form a sufficiently stable stand for the more prolonged,
but still short, exposure that he may be required to give on some
particular subjects such as a photograph at sunrise or near sunset.
Photographers in England are rarely afflicted with breathlessness
through exertion, but it is different in mountaineering. A
mountaineer may keep his wind, but it would be rare to find that his
heart was beating equably after some spurt of exertion, such as rock
climbing. It is often after some such exertion that he comes upon
some view which he may wish to record on his photographic plate. The
usual method of holding the hand camera would under such
circumstances prove a failure so far as sharpness of image is
concerned. Pressed against his "middle" or "upper" chest, the
beatings of the heart will record themselves on the photograph.
Under such circumstances resort must be had to some form of support
on which to rest his camera. After many years' experience, the
writer has come to the conclusion that there is no support superior
to the ice axe. It is not necessary to cause it to stand upright in
the ground, ice, or snow, though this should be done if possible. It
will suffice to rest the point on the rock, and place the camera on
the axe head, with the pick parallel to the body. We then have a
firm support in one direction, and the hands, which are not affected
by the automatic motion of the heart, can be trusted to keep it
steady in the other direction. Photographs taken with a good lens,
and with such a stand, will bear enlarging up to 22 inches, at
least. It is because these photographs will bear enlarging that a
small plate is recommended to the mountaineer. There is not a large
proportion of Alpine views taken on the mountain side of which one
would care to have anything but a memorandum, and it is such a size
as that recommended which gives such a memento, and which, if
desired, allows a more formidable size to be acquired at home, where
we may suppose there are all the conveniences that a photographic
laboratory affords. The writer has had experience on mountains with
cameras varying from 12 × 10 to the 1/4 plate size. When younger and
more inclined to waste a few valuable minutes of daylight in putting
up a camera stand, the 12 × 10 gave pictures which we often lamented
having taken, whilst in his more mature years, a snap-shot has never
been regretted. The cameras which require stands, require one porter
at least to carry them, for although the late Mr. Donkin carried his
own 7-1/2 × 5 camera up the highest peaks, it is few men, who, even
if they had the energy or the physique that he had, would imitate
his example. A porter means an extra expense in fees, and an extra
mouth to feed, and very likely entails slowness in a climb through
having an additional man upon the rope. A quarter plate or a 5 × 4
camera the owner, however, can himself carry; but the best form of
attaching it to his body has been a difficult task to evolve. Many
and many different attachments have been tried. One thing is quite
certain, and that is, the camera should be in a stout case, but it
cannot be carried over the shoulders by a strap as we can do in
comparatively level countries. Let anyone try to come down a rock
with the camera slung over his shoulders, and he will soon find it
dangling in front of his stomach, or swinging like a pendulum, and
threatening to displace him from what at best may be a treacherous
handhold. The method of attachment we adopt now, will be readily
seen from the diagram.
[Illustration]
The shoulder strap is utilized, but a ring is attached to the back
of the case as shown, and a strap or piece of whipcord comes over
the strap as shown. The two shoulders are in AA and the case is
carried as a knapsack. The length of the cord or strap BB is so
adjusted, as is also the length of the shoulder strap, that the
camera lies against the small of the back, and that it will not
swing away from the body. At one time the ring was placed in front
of the case, but the result was merely to cause the top of the case
to rest against the back. The plan shown above has answered under
almost every variety of circumstances, and the weight is
inconsiderable. (A friend has his camera attached to the bottom of a
small "rücksac" and this answers, but as the writer does not carry
his own provisions or change of garments he has not adopted this
plan). A long day's march may be undertaken if this contrivance be
employed, and the weight is scarcely felt.
For those who have not had extensive practice with hand cameras, a
view finder is, if not a necessity, at all events, a great help. On
the whole, perhaps the best form is that in which a miniature view
falls on a ground glass. It must be recollected, however, that each
view finder is adapted for some particular focal length of lens.
The view in the finder and on the plate should be compared, and if
the former is more extensive, the surplus ground glass should be
covered up with a black mask.
If it be determined to take a camera with its stand, very few
directions are required beyond those which apply to ordinary view
work on the plains. It may perhaps be as well to mention that a
camera stand placed on ice or snow, is not immovable until the iron
shoes of the legs attain the temperature of the surrounding snow or
ice. An exposure of a few seconds will often show an image which has
moved on the plate.
The next point that we may call attention to is the plate to be
employed. With a hand camera there is no absolute necessity to have
the most rapid plate, as far as exposure is concerned, but in
mountain work it must be recollected that there are very great
contrasts to represent on the print. "The slower the plate the
steeper the gradation" is almost axiomatic, and it must be
recollected that only a certain amount of opacity will print if the
deepest shadows only are to be kept of the greatest black obtainable
in a print. It is evident that the greater the range of light and
shade that is obtained of a printable density, the more true to
nature the picture will be. For this reason a quick plate with a
moderate gradation is to be preferred--as being most generally
useful--but it should be a plate which is absolutely free from fog,
and it should also be of as fine a grain as possible, the size of
which has something to do with development. This is still more true
when a camera stand and hand exposures are made. With a slow plate
with feebler intensities of light, which must be the case when the
lens is stopped down to admit of hand exposures, the gradation
becomes more steep than if a fairly bright light be employed. A
quick plate does not suffer in the same way, however small the stop
may be. It has already been stated that isochromatic plates may be
employed with a hand camera. For ice and snow views there is not
much to commend their employment, unless to give a deeper shade to
the sky and to the vast crevasses which so often form part of the
foreground. The darker sky allows faint clouds to be visible in a
print when they otherwise would be absent. Pictorially thus the
isochromatic plate has something to recommend it. Celluloid films
have often been substituted for plates by the writer, and excellent
photographs have been obtained on them when they were fairly rapid.
There is not much to be said in their favour as regards weight, for
in most cameras the support for them weighs nearly as much as the
glass plate. There is also a disadvantage in developing them, for
they are not so easily manipulated as a rigid body. For convenience
in travelling, however, they are to be highly commended. A gross of
cut films do not weigh so much as a dozen plates and occupy much
less space in the baggage. The question of the use of a Kodak camera
with its roller slide, has not been brought forward, not because
excellent results cannot be obtained with it, but simply because the
writer prefers to use plates and films which can be got at any time
for the purpose of development.
For travelling on the continent, and to one's mountain destination,
experience has shown that a small hamper is the safest receptacle of
all the necessary kit. A hamper which will contain two camera cases
side by side is really sufficient; but it should be a little greater
in depth. It may be thought that two cameras are to be taken, but
such is not the intention. If a zinc trough be made of the size of
one camera case it will contain all the developing apparatus
necessary, the lantern, and the plates or films, and all the few
etceteras which go to make one happy. (A screwdriver, a file, and
some extra screws, and gummed paper and white blotting paper cut to
the size of the plates should be enough for the etceteras). The
hamper may be arranged so that the camera and view finder may be
taken out without any derangement of the rest of the articles in it.
The developing bottles and cups, with the dishes, may be similarly
extracted. This prevents undue trouble in unpacking and packing. One
grand thing to remember is, pack well but not distressingly tightly,
in other words don't employ an expert packer if you wish for comfort.
Have the hamper a size too large rather than a size too small. Also
be it remembered that it is useless to stopper the bottles with all
sorts of devices at home, and have to pack in an ordinary manner when
once the contents of the hamper have been brought into use. Have your
bottles covered with an indiarubber cap which can easily be removed
and replaced; of course we are assuming that development is to take
place during one's travels, and not to be left over for home.
Personally we think that a speedy development after a view is taken
will give the best picture. It may often happen that an undeveloped
sensitive plate or film will suffer by its travels. There will or may
be scratches and what not, which would be absent if the negative is
finished at the time. The outfit for development which need only be
taken is as follows: four developing dishes, bottles or cartridges of
the dry developer, ammonia diluted to half its strength in a glass
stoppered bottle (if in a wooden case, as for medicine bottles, it
will be a further protection), a couple of tins of hyposulphite
_pounded up_ before the journey, carried in small tins (such tins as
the half-plate platinum paper comes in are very convenient), two or
three empty six ounce medicine bottles with good corks, a two or
four ounce measure, a washing rack with a trough (there is a
folding rack in the market which answers admirably; it has =v= shaped
grooves which never damage the edges of the film, and one rack will
take twenty-two glasses back to back). A zinc trough can be made to
cover the plates with water when in the rack, a lantern (by
preference a paper folding one), a dusting brush, a couple of
dusters, and blotting paper cut into squares the size of the plates,
with which to pack them--it is useful also to have spare pieces of
blotting paper to place beneath the plates when drying, also a piece
of mackintosh to place on the wash stand during developing
operations--an empty pint wine bottle will be got at any hotel and in
this the hyposulphite can be dissolved. The list looks formidable but
the whole can be readily packed in the hamper of the size given. It
will be seen that no intensifying solutions are enumerated amongst
the requisites. A negative is better strengthened in the quiet of
one's dark-room at home.
[Illustration: HOMEWARDS. KARL GREGER.]
Now we must give a hint or two as to the exposures required. We will
suppose that on the plates to be used a satisfactory negative of an
open English landscape, on a bright June day with fleecy clouds in
the sky, can be secured with an aperture of _f_/11 in 1/25th of a
second. If that be so, then on an equally fine day in July or
August, at an altitude of about 6000 feet, the same kind of view
should theoretically be secured in 1/50th second, and a stop of
_f_/16--that is, the photographic light is about four times as
strong. It must, however, be recollected that at this altitude, and
particularly near mid-day, the shadows are not illuminated to the
same degree from the sky. The darker blue sky shows that the light
which at a low altitude goes to make a pale blue sky is to be found
in the direct rays of the sun, and not scattered to give a luminous
sky. As the shadows are principally illuminated by the light from
the sky, it follows that the shadows will be darker at a high than
at a low altitude, for this reason amongst others, the exposure
should not be curtailed to the amount given above. If the aperture
be reduced to _f_/16 it is probable that the exposure of 1/25th
second will be not more than sufficient to give. For our own part we
prefer to give longer and to expose well for the deep shadows,
trusting to development to give us properly "gradated" pictures. As
the sun goes down toward the horizon, the shadows get more illumined
from local reflection, and it is scarcely necessary to alter the
exposure until considerably nearer sunset than at home, when the
exposure must be considerably prolonged. For views in which there is
little but ice and snow, the exposure should be very much curtailed.
There is so little contrast that if the exposure be at all prolonged
the picture will be inevitably flat. The shadows are illumined by an
immense quantity of light reflected from the white surface, and the
difficulty is to get sufficient contrast. The writer well remembers
one set of beautiful views, taken from the top of a mountain some
10,000 feet high, where the eye could see nothing but snow-fields
and ice and swirling masses of clouds. The day was not bright, but
to get a satisfactory picture a stop of _f_/32 was necessary with
only an exposure of 1/70th of a second. Plates given an exposure of
1/25th second with a stop _f_/16 showed little besides a plain white
mass. It would be difficult to give hints for every kind of view.
The judgment of the operator must be brought into play and no
actinometer will be of much use under the varied conditions which
are the rule, not the exception.
Now as to development. The "one-solution" given by the metol and
amidol cartridges are the most readily prepared, and in five times
out of six will scarcely be bettered, but for the sixth time may
fail, because of their "rigidity." For these exceptional negatives,
solutions of an oxidizing agent such as pyrogallol, of a restrainer
(bromide), and of an accelerator are to be recommended. For the
latter, the carbonate (not the bicarbonate) of potash is much to be
recommended, though some prefer ammonia. Two formulæ are given,
either of which will be found extremely useful. When the exposure
has been prolonged enough for details in deep shadows to be brought
out, it will generally happen that over-exposure has been given to
the high-lights, and it is to keep these in the printing state that
care is required. In the old collodion dry plate days, it was very
usual to bring out a complete phantom image of a subject before any
density was given to it. When this was properly out, the intensifier
of silver nitrate and pyrogallol was applied, and the picture
gradually brought up to printing density. It was usually full of
detail in the high-lights and shadows, all of which would be found
in the finished print. Such is the same procedure which we
recommend, strive to get out an image of feeble density but full of
detail, and then give the density.
The plate should first of all be thoroughly soaked in a solution of
the alkali which can be used, and then a few drops of the pyrogallol
solution be dropped into the developing cup with an equal number of
drops of the restrainer. The alkaline solution is then returned to
the cup and again poured into the dish and over the plate. By
degrees the required phantom image will make its appearance, and now
bromide and pyrogallol are added until it is evidently complete. The
plate is then washed in water, a final wash being given in a very
weak solution of acetic acid or citric and water. After a final
rinse with water the plate is treated with the pyrogallol solution
and restrainer in the proportion recommended for the ordinary
development of the plate, omitting the alkali. The density will
begin to appear, and when it flags, a little alkali is added (a few
drops at a time) to the solution. Keep the image fairly feeble at
above half the proper printing density, and fix. The plate should
then be kept for intensification, preferably by Mr. Chapman Jones's,
when a mercury solution is applied, and then a ferrous oxalate to
reduce the latter to the metallic state. It will be found if this
procedure is adopted, that the negative is built up with a greater
range of light gradation than by bringing it out by a one-solution
method of development. If one wishes to exercise artistic treatment,
then in the preliminary stage more importance can be given to any
desired part by applying a camel's hair brush soaked in normal
pyrogallol solution with its restrainer. The prominence thus gained
will be kept in the subsequent operations. When applying the brush
care must be taken that the image blends as it were with the rest of
the picture. No abrupt increase of density must be permitted, as if
it be, the result will be anything but satisfactory.
The following is an ammonia-pyro developer, with which the writer
usually works.
A
Ammonia 1 part.
Water 9 parts.
(Of course, should the ammonia be taken half strength allowance must
be made for the dilution.)
B
Potassium bromide 20 grains.
Water 1 ounce.
(When travelling it is very convenient to have the bromide weighed
out into 20 grain packets.)
P
Pyrogallol dry.
S
Saturated solution of sulphite of soda.
When the view has strong contrasts and the plate has been exposed
for the shadows take of A 30 minims and 2 ounces of water and soak
the plate in it as given above. Then add to the cup, of B 2 drams,
of S 1 dram, and about quarter grain of P. Pour back the solution of
ammonia from the dish, and then apply the mixture till all detail
appears, and proceed as indicated above. A saturated solution of
potassium carbonate may be substituted for the ammonia solution.
Before closing this chapter it may be of use to the reader to
tabulate the number of thicknesses of atmospheres through which
light has to travel at different altitudes of the sun at sea level.
Altitude. Atmosphere.
90° 1.000
80° 1.015
70° 1.064
60° 1.155
50° 1.305
40° 1.555
30° 1.995
20° 2.904
15° 3.809
10° 5.571
5° 10.216
4° 12.151
2° 18.882
0° 35.503
If sunlight outside the atmosphere be represented by 1 and say
1/10th be cut off by 1 atmosphere, then after transmission through 2
atmospheres only .81 will reach the spectator, and if through 3 only
.729. For any atmosphere the diminution will be 1/10th, that is, it
will be .9^_x_ where _x_ is the number of atmospheres.
If we ascend the factor varies, there are less thicknesses of
atmosphere to go through and we get the following table.
Photographically
Visual Transmission Actinic Light
Barometer (Sunlight outside Transmitted
in Inches. the Atmospheric (Sunlight outside
being 1). the Atmospheric
being 1).
30 .853 .639
29 .866 .654
28 .875 .672
27 .884 .689
26 .891 .708
25 .899 .730
24 .908 .746
23 .915 .763
22 .922 .787
21 .928 .800
20 .934 .819
19 .940 .833
This table and the preceding one will enable a calculation to be
made as to the exposure to be given. Thus at sea level with a
photographic brightness of sun of 639,000 candles when nearly
overhead, it will at 5° above the horizon only have a photographic
brightness of about 1000. At about 9000 feet high the photographic
brightness would when the sun is overhead be about 800,000 candles,
and at 5° it would have a value of 350,000, showing the greater
penetration through the thinner atmosphere.
_W. de W. Abney, C.B., F.R.S., etc., etc._
Negative Making.
DEVELOPMENT, INTENSIFICATION, REDUCING, Etc.
[Illustration]
When a sensitive plate has been properly exposed under ordinary
conditions, there is no visible change. The action of light produces
what is known as a _latent image_ or _developable image_, and in
order to convert this into a visible image with sufficient opacity
to be useful for printing purposes, it must be _developed_. In the
operation of development, the plate is treated with some solution
that will act on the exposed parts of the sensitive film and reduce
the silver salts contained therein to metallic silver, in quantity
proportional to the amount of light-action, whilst at the same time
it produces no appreciable change in those parts of the film on
which light has acted the least or not at all, and which correspond
to the darkest shadows of the object that has been photographed. The
solution used for this purpose is called the _developer_.
DEVELOPERS--GENERAL.
The substances that can be employed as photographic developers are
now somewhat numerous, but the most useful for negative making are
pyrogallic acid (also known as pyrogallol, or for brevity as pyro.),
ortol, metol, and hydroquinone (also known as quinol). Ferrous
oxalate is likewise used in special circumstances, but not for
general work. An ordinary developer as mixed for use contains:--
1.--One of the above-mentioned substances (pyrogallic acid,
ortol, metol, quinol) which is the actual developing
constituent, and is known as _the reducer_, but requires the
addition of the next constituent before it can work.
2.--An alkali, which may be sodium carbonate, potassium
carbonate, caustic soda, caustic potash, or, if pyrogallic
acid is used, ammonia. The alkali sets the reducer in action
and is called _the accelerator_.
3.--A soluble bromide, which must be potassium bromide
except when ammonia is used as the alkali, and then it may
be ammonium bromide. The chief use of the bromide is to
retard the action of the developer, and in particular to
prevent its affecting those parts of the film that have not
been acted on by light. For this reason the bromide is
called _the restrainer_ or, sometimes, _the retarder_.
4.--A sulphite, the function of which is to prevent the
solution from becoming strongly discoloured and consequently
staining the film. It also affects the colour of the reduced
silver that forms the developed image, this colour being
browner, and consequently of higher printing opacity, the
lower the proportion of sulphite present. Sodium sulphite
and potassium metabisulphite are the most commonly used.
The composition of a developer has to be so arranged that, whilst
reasonably rapid in its action, it is not so rapid as to be beyond
control, and does not produce "general fog" by acting on those parts
of the film that have not been acted on by light.
[Illustration: AMONG THE ALPS. CAPT. W. DE W. ABNEY, C.B., F.R.S.
ETC.]
DEVELOPMENT--GENERAL OPERATIONS AND PHENOMENA.
A developer is usually compounded immediately before use by mixing
two or more solutions, and in order to ensure uniform action it is
essential that the constituents should be thoroughly mixed before
the liquid is applied to the plate. If the measuring or mixing
vessel is large enough, this can be done by agitating the liquid; if
not, the liquid may be poured once or twice from one vessel to
another.
The quantity of developer necessary for a plate of a given size
depends in some degree upon the size and character of the dish that
is used, and is smallest when the bottom of the dish is quite flat
and has no ridges or grooves. It is false economy to use too small a
quantity, and it may be taken that for a quarter plate 1-1/2 oz.,
for a half plate 2-1/2 or 3 oz., and for a whole plate 4 oz. of
developer should be used.
Ebonite, xylonite, or papier maché dishes are the best for all
operations connected with negative making, since they are not so
liable as porcelain or earthenware to break a plate if it is allowed
to drop into them.
When applying the developer to the plate it is important to cover
the whole surface of the plate rapidly and in such a manner as to
avoid the formation of air bubbles, and the best way is to begin to
pour on the developer at one corner of the developing dish and
whilst pouring somewhat quickly move the vessel rapidly but steadily
along the edge of the dish to the other corner. If there should be
any froth or air bubbles on the surface of the developer, the last
portions should not be poured out of the vessel into the dish, and
then the risk of air bubbles forming on the surface of the plate
will be lessened.
Sometimes after the developer has been poured on and the plate seems
to be uniformly wetted, the liquid will recede from one corner or
one edge of the plate and the part thus left uncovered will appear
as a patch of lower opacity when the negative is finished. This
happens either because the dish is not standing level on the table
or because the bottom of the dish is not flat; sometimes it happens
because too small a quantity of developer has been used.
After the plate has been covered by the developer the dish should be
carefully rocked from time to time, and, for reasons that will be
explained presently, the time required for the first appearance of
the image and the manner in which the different parts of the image
follow one another, should be carefully observed.
If the plate has been correctly exposed, the brightest parts of the
image will appear (as black, of course,) in about a minute, more or
less, according to the temperature, composition of the developer,
and character of the plate, and the other parts will follow steadily
in the order of their brightness, after which the image as a whole
will continue to gain vigour or opacity up to a certain limit. The
essential point is that the principal details in the deepest shadows
of the subject shall appear and acquire a distinct printable
opacity, before the highest lights become so opaque that the details
in them are no longer distinguishable. Whether this condition is
realisable or not depends very largely on the exposure that the
plate has received.
If the image appears in considerably less than a minute and the
different parts follow one another very quickly, the plate has been
_over-exposed_, and the degree of over-exposure is indicated by the
rapidity with which the image appears. In this connection it ought,
however, to be stated that with metol and certain other developers,
even when the plate has been correctly exposed, the different parts
of the image appear almost simultaneously, though the first
appearance may not begin until about a minute after the developer
has been applied to the plate. It follows that with these developers
it is difficult to recognise over-exposure, but it so happens that
they are not suitable developers to use when there is any
probability that the plates have been over-exposed. On the other
hand, if the image is slow in appearing and the brightest parts of
the subject are not followed in due course by the middle tones, the
plate has been _under-exposed_, and there is considerable danger
that the high-lights may become quite opaque before any details have
appeared in the shadows, or even, in extreme cases, in the lower
middle tones, that is to say, in those parts that are next in
darkness to the shadows.
When it is desired, as it frequently is, to alter the composition of
the developer during development, the substance or substances to be
added should be put into the measuring or mixing glass, the
developer poured out of the dish into the glass, and the well-mixed
liquid poured over the plate as before. Any attempt to add
substances to the developer whilst it is in contact with the plate
will probably result in uneven action.
It should be borne in mind that temperature has an important
influence on development, the time required for the first appearance
of the image and for the completion of development being, as a rule,
less the higher the temperature. Further, if the developing
solutions are very cold, it is often almost impossible to obtain
sufficient opacity.
Perhaps the most difficult thing in connection with development is
to know when to stop the process, that is to say, when the image has
acquired sufficient opacity, or "density," as it is often called.
After all the required detail has become visible, the plate from
time to time is lifted carefully out of the developer, allowed to
drain for a moment or two, and then held between the developing lamp
and the eye; the opacity of the image, especially in the highest
lights and deepest shadows, being carefully scrutinised. The
appearance of the image as seen when looking at the back of the
plate, is also carefully observed.
For this purpose it is very much better that the light of the
developing lamp should pass through transparent glass (ruby or deep
orange) so that the flame itself is distinctly visible, instead of
through ground glass or a coloured translucent fabric. Further, the
flame of the lamp, whether gas or oil, should always be turned up to
the same height, for it is clear that if the brightness of the flame
used for making the examination is not fairly constant, all sorts of
variable results will be obtained. For this reason it is much better
to judge the opacity of negatives by artificial light than by
daylight, the intensity of the latter being so variable. A paraffin
lamp with a circular wick and a deep ruby chimney with a metal cap
at the top, answers admirably.
No general rules can be laid down; the appearance of the properly
developed image depends on the thickness of the film, the
granularity of the silver salt, the presence or absence of silver
iodide, and the composition of the emulsion used. Experience only is
of value, and the best way to secure uniformly satisfactory results,
is to keep as far as possible to one brand of plates. With some
plates, for example, very little of the image should appear at the
back of the plate, with others the greater part of the image must be
distinctly visible there.
Sometimes, especially when using small sizes of plates, it is not
easy to tell whether all the necessary detail in the shadows has
been brought out, and this is an important matter, for if the small
negatives are to be used for making enlarged negatives or prints, or
lantern slides, there should be very little clear glass indeed even
in the deepest shadows of the subject. As a rule it may be said that
when every part of the image is at least gray the maximum possible
amount of detail has been brought out. If the greyness begins to
spread to the margins of the plate where it has been protected by
the rebate of the dark slide, general fog is being produced, and, as
a rule, little will be gained, but much may be lost, by continuing
the development for any considerable time after this is observed.
When development is completed the developer is poured off, the plate
is well rinsed under the tap or in two or three changes of water,
and is then ready for fixing.
DEVELOPMENT WITH PYRO-AMMONIA.
This method of development has the advantage that the constituents
can be kept in concentrated solutions, considerable modifications in
the composition of the developer can be made very readily and the
negatives obtained are of excellent printing quality. On the other
hand it cannot be satisfactorily employed with certain brands of
rapid plates, because with them it has a tendency to produce general
fog, and with some other plates, especially when they are old, it
has a tendency to produce what is known as green fog.
Three solutions are prepared:--
REDUCER.
Pyrogallic acid 1 oz. or 10 parts
Potassium metabisulphite[1] 1 oz. or 10 parts
Water, to make up to 10 oz. or 100 parts
ACCELERATOR.
Ammonia 1 oz. or 10 parts
Water, to make up to 10 oz. or 100 parts
RESTRAINER.
Ammonium bromide 1 oz. or 10 parts
Water, to make up to 10 oz. or 100 parts
[1] The metabisulphite is dissolved in about 8 oz. (80 parts)
of water with the aid of heat, and the pyrogallic acid is
then added. When the liquid has cooled it is made up to 10
oz. (100 parts) by addition of water, the whole being well
mixed by shaking.
For each ounce of developer, take 20 minims of reducer, 20 minims of
restrainer and 40 minims of accelerator, and make up to 1 oz. with
water. With some plates 60 minims of accelerator and 30 minims of
restrainer may be used, but any greater proportion of accelerator
has considerable tendency to produce general fog. On the other hand
the proportion of restrainer can often be increased with advantage
since, unless the amount added is very large, its chief effect is to
prevent general fog; 30 minims of restrainer to 40 minims of
accelerator, or 40 minims of accelerator to 60 minims of restrainer
are proportions that can be recommended. Too low a proportion of
bromide should be carefully avoided.
It is very important to ascertain, by careful trial with each brand
of plates that is to be used, what is the maximum proportion of
ammonia that can safely be added, and what proportion of bromide to
ammonia is necessary in order to prevent general fog. As a rule, the
more rapid the plates the smaller is the quantity of ammonia that
can be used with safety.
By far the best plan is to keep development well under control by
adding only part of the accelerator at the beginning of development
and adding the rest as circumstances require.
For each ounce of developer take 20 minims of pyro solution and make
up to the required bulk with water. In another measure mix for each
ounce of developer 40 minims of bromide solution and 60 minims of
ammonia solution, and regard this as the maximum quantity that can
be added with that bulk of developer. Now to the diluted pyro
solution add about a quarter or one-third of the ammonia and bromide
solution, pour this mixture on the plate and observe what happens.
If the mode of appearance of the image indicates that the plate has
been correctly exposed, about half the remaining ammonia and bromide
mixture may be added to the developer at once, and the action
allowed to continue, with occasional rocking of the dish. If
development proceeds satisfactorily and, in particular, if the chief
details in the shadows begin to appear before the highest lights
have become too opaque, it is not necessary nor advisable to add the
last portion of the ammonia and bromide mixture, since the tendency
to general fog and green fog is reduced when the proportion of
ammonia is kept as low as possible. On the other hand, if the
development flags and the appearance of shadow detail is a little
tardy, the rest of the ammonia and bromide mixture must be added.
If the plate seems to be over-exposed, no more of the ammonia and
bromide mixture should be added for some time, until it is seen
whether the quantity already in the developer will suffice to
complete development. If it seems that the over-exposure has been
considerable, a further quantity of pyro solution (10 to 20 minims
per oz.) and also of bromide solution (10, 20, or 30 minims per oz.)
may be added with advantage. Development is then allowed to continue
and the negative is examined from time to time; if it is seen that
the opacity does not increase, or if sufficient detail in the deep
shadows does not appear, further small quantities of the ammonia and
bromide mixture may be added _cautiously_ until the required result
is obtained, waiting a little while to see the result of each small
addition before adding more.
When the plate behaves as if under-exposed, dilute the developer at
once with half the quantity or an equal quantity of water, according
to the degree of under-exposure indicated, and add the whole of the
ammonia and bromide mixture. These modifications should check the
rate at which the high-lights of the subject gain opacity, whilst
accelerating the appearance of the middle tones and shadows. Should
this effect not be produced, further quantities of ammonia and
bromide mixture may be added or, in extreme cases, ammonia alone,
and the developer may be still more diluted with water.
If any considerable parts of the image still show no detail, local
development with a brush may be tried as a last resource. A soft
camel's hair brush, preferably mounted in quill, is used. Some of
the ammonia and bromide mixture is placed in a vessel and diluted
with two or three times its volume of water. One corner or edge of
the plate is raised so that the part to be treated is lifted out of
the developer, the diluted ammonia and bromide mixture is applied
rapidly with the brush, and the plate is allowed to drop gently back
into the developer. The treatment may be repeated if necessary.
Should all these devices fail, the plate is hopelessly
under-exposed.
Sometimes, when working with a diluted developer as just described,
it happens that although all the necessary detail has been brought
out, the image gains in opacity very slowly. Provided that all the
required detail is visible, small quantities of pyro solution may be
added in order to gain opacity more quickly.
[Illustration: TEASELS By Carine Cadby.]
PYRO-SODA DEVELOPMENT.
When sodium carbonate is used as the alkali in place of ammonia the
developer acts somewhat more slowly and is less liable to produce
fog, especially with very rapid plates, and there is very little
tendency to produce green fog. On the other hand, variations are not
so easily made in the composition of the developer. Some people find
the absence of the smell of ammonia a decided advantage.
STOCK PYRO SOLUTION.
The same as for Pyro-Ammonia.
DILUTE PYRO SOLUTION.[2]
Stock pyro-solution 1 oz. or 10 parts
Water 10 oz. or 100 parts
SODA SOLUTION.
Sodium carbonate, crystallised. 1 oz. or 10 parts
Sodium Sulphite 1 oz. or 10 parts
Potassium bromide 10 grains or 0.23 part
Water to make up to[3] 10 oz. or 100 parts
[2] No more of the dilute pyro solution should be made up
than is likely to be used during the same day, but it will
keep well enough for a day or two.
[3] The sodium sulphite and carbonate are dissolved, with the
aid of heat, in about 8 oz. (80 parts) of water, the bromide
added, and the liquid when cold made up to 10 oz. by adding
water.
For use mix equal parts of dilute pyro solution and soda solution
and pour over the plate.
If the exposure has been correct the image will begin to appear in
about a minute, and development is then allowed to go on with
occasional rocking of the dish, until the negative is sufficiently
opaque.
If the plate behaves as if it were under-exposed, _at once_ dilute
the developer with an equal bulk of water and pour it back over the
plate. If the high-lights continue to increase in opacity, but the
rest of the image does not appear, add some more of the soda
solution with or without some more water. Should parts of the plate
still remain blank, apply some of the soda solution to them with the
aid of a brush as described under pyro-ammonia (page 32).
If the rapid appearance of the image indicates that the plate is
over-exposed, at once pour off the developer into a measure or
mixing glass and rinse the plate well with water. Add to the
developer a small quantity of potassium bromide solution (1 in 10 of
water) which should be kept at hand for this purpose. A small
quantity of pyro stock solution may also be added. The developer is
then poured over the plate again. When the over-exposure seems to
have been considerable, the amount of potassium bromide added may
amount to 4 grains (or 40 minims of the 1 in 10 solution) per ounce
of the developer, but this proportion should not be exceeded; even
small quantities of bromide in the pyro-soda developer have a marked
influence in retarding development.
When there is reason to suspect over-exposure, not more than half
the soda solution should be added at the beginning of development,
and the rest may be added or not, as the case may require.
DEVELOPMENT WITH ORTOL.
ORTOL SOLUTION.
Ortol 130 grains or 1.5 parts
Potassium metabisulphite[4] 65 grains or 0.75 part
Water to make up to 20 ounces or 100 parts
SODA SOLUTION.
The same as for pyro-soda.
[4] See foot-note to page 30.
Mix equal parts of ortol solution and soda solution.
This developer behaves in much the same way as pyro-soda and gives
very similar results. It has the advantage, however, that it does
not stain the fingers, and has practically no tendency to produce
either fog or stain on the plates. Moreover the same quantity of
solution can be used for several plates; when the action becomes
perceptibly slower or weaker, part of the old solution is poured
away and an equal quantity of freshly mixed ortol and soda solutions
is added.
The chief differences to be observed are (1) that the different
parts of the image follow one another more rapidly than with
pyro-soda, even though the plate may have been correctly exposed,
and (2) the colour of the reduced silver is somewhat bluer than with
pyro-soda, and therefore in order to obtain the same degree of
_printing_ opacity, as distinct from visual opacity, development
must be carried a little further.
Apart from these differences, what has been said of pyro-soda holds
good for ortol soda and need not be repeated.
DEVELOPMENT WITH HYDROQUINONE (QUINOL).
QUINOL SOLUTION.
Hydroquinone 90 grains or 2 parts
Sodium sulphite 1 oz. or 10 parts
Water to make up to 10 oz. or 100 parts
ALKALI SOLUTION.
Potassium carbonate (dry) 1 oz. or 10 parts
Potassium bromide 20 grains or 0.46 parts
Water to make up to 10 oz. or 100 parts
Mix two parts of hydroquinone solution with one part of alkali
solution and one part of water, or, if a more energetic developer is
wanted, mix equal volumes of the hydroquinone and alkali solutions.
Hydroquinone is not an advantageous developer for general purposes,
but it is useful when negatives are required showing strong contrast
between the highest lights and the deepest shadows, and especially
when it is important that there should be no deposit at all in the
deepest shadows. This is the case, for example, when copying line
engravings, pen and ink drawings and similar subjects.
DEVELOPMENT WITH FERROUS OXALATE.
This method of development also is not well adapted for general
work, but it is invaluable for certain purposes. The reduced silver
has a pure grey-black colour and there is exceedingly little
tendency to produce fog of any kind. On the other hand, the
developer admits of little modification in its composition and
therefore the exposure must be fairly correct. It is also important
to avoid contamination with even minute quantities of hypo, since
this substance very readily causes stains.
FERROUS SULPHATE SOLUTION.