mind. If we are copying in the camera with daylight as illuminant it
is very important to use the light from the north; if we use other
light we shall be much put out on most occasions by awkward
variations of the brightness. A very large number of operations are
rendered nugatory by carelessness in this matter. Even the most
experienced worker will find it impossible to expose plates with
anything like accuracy when he has to deal with direct sunshine at
one time, thin white clouds at another, and dark clouds at a third.
And in making exposures by contact the beginner must be fairly
accurate in judging the time of exposure and the distance from the
radiant. A good plan is to tie to the gas jet a piece of cord having
knots at convenient intervals, such as at 9, 12, 18 and 24 inches,
and in making an exposure to use these knots as guides to the
distance; moreover, the law of "squares of distance" must be
remembered; the intensity of light varies inversely as the square of
distance from radiant to receiver, provided, of course, no optical
arrangement is introduced to modify the path of the rays.
Consequently, for example, if ten seconds is found to be a proper
exposure at nine inches from the light, the corresponding exposure
at eighteen inches will not be twenty, but forty seconds (9^2=81.
18^2=324). And as it is sometimes awkward to hold the frame and
attend to a watch at the same time, a metronome, ticking seconds,
will be found convenient, or a clock with a second hand may be
placed where it can be seen during the exposure. A landscape slide
without clouds, if the horizon is in the picture, is usually
considered a failure, and has been dubbed "bald-headed." Really good
workers often put clouds into slides by "combination printing,"
which in some cases is comparatively easy, in others very difficult.
If we are working by reduction from a good-sized negative, with a
fairly even horizon, the difficulty is not great. The landscape part
of the negative is first exposed, the sky being masked if necessary,
and a cloud negative is then substituted for the landscape negative,
a part of the former being masked to correspond with the landscape
on the latter, and a second exposure is made on the same
slide-plate. Admittedly in all cases this requires "some doing," in
many cases it is extremely difficult. An easier, if less
"sportsmanlike," method is to make the cloud slide on a separate
slide-plate, and to use the latter as a "cover-glass" for the slide.
The cloud may cover the whole of the second slide, and that part of
it not required may be wiped out by means of a reducing solution,
used with a brush, such as the ferricyanide and hypo one described
later. This method will be found useful even in contact slide
making, but it also requires not only good taste in the selection of
the cloud, but some deftness in manipulation; but the neat-handed
beginner need not fear to make the attempt.
DEVELOPMENT.
It has already been stated that judgment of exposure is a matter of
experience, and that results are the best criterion; here follow
some more explicit statements on the same matter.
Whatever plate or developer is used, and whatever the time occupied
in complete development:
_1st._--If by the time the high-lights are sufficiently
strong the shadows are too dense or blocked, the plate has
been under-exposed.
_2nd._--If by the time the high-lights are sufficiently
strong the shadows have not attained sufficient density, or
are veiled, the plate has been over-exposed.
_3rd._--If at the same moment the high-lights show
sufficiently and the shadows are transparent but
sufficiently plucky, the plate has been properly exposed.
_4th._--With a normal negative the normal exposure is the
proper exposure; but (_a_) a negative abnormally strong in
contrasts will require an abnormally long exposure; and
(_b_) a thin negative, or one with a very short scale of
gradation from densest to clearest, will require an
abnormally short exposure, with probably some
after-treatment in the direction of "intensification."
Ambitious slide-makers generally aim at warm-toned slides for
pictorial effect, and rightly. But slides intended for scientific
purposes are generally better when cold in tone, the definition is
usually better. But whatever the aim, a good tone of one kind is
preferable to a poor one of another kind, and the beginner should
first make sure of getting a really good cold tone, which is
comparatively easy, and then try his "'prentice hand" on warm tones.
Warm tones are obtained by using greatly super-normal exposures and
greatly restrained developers; and the danger probably lies in the
fact that the long exposures are apt to lead to fog, and the great
restraint to over-density in the shadows, the latter especially when
the exposure has not been quite long enough for the developer used;
herein probably lies the whole secret of warm slide-making. If we
aim at really warm tones and use developers suited to such design,
we must on no account stint the exposure.
COLD TONE DEVELOPING SOLUTIONS.
[Illustration]
The classical solution for cold tone slides is a solution of ferrous
oxalate in potassic oxalate. Of all developers it is most free from
fogging propensities. It is made from so-called "saturated
solutions" of proto-sulphate of iron and potassium oxalate. Thus,
into a bottle put a quantity of iron proto-sulphate, and pour on
about three times its weight of water containing a dram of sulphuric
acid to each pint. Shake well, and keep always at about 60° Fahr.;
some of the iron must always be visible in the bottle, if not, more
is to be added. The crystals of iron salt must be green and not
rusty in colour. This is the "iron solution."
The "oxalate solution" is made by dissolving potassium oxalate in
about three times its weight of water. This also must be kept at 60°
Fahr., shaken occasionally, and oxalate added if none is visible in
the bottle.
To make the ferrous oxalate solution we _pour_ one part of the iron
solution _into_ six parts of the oxalate, and it is advisable to add
to each ounce of developer at least half a grain of potassium
bromide; 5 minims of a 10% solution, made by dissolving one ounce of
the bromide in about 9 ounces of water, and then making up to 10
ounces--all chemical.
In about four minutes or less this ought to fully develop a properly
exposed plate. If the development is much shorter the slide is apt
to have an unpleasant greenish tone, a result that may also follow
the use of an inordinate amount of bromide in the developer. The
developing solution may be made in quantity greater than is required
for one plate, and may be used several times if a little of the
surplus and fresh solution is added when the quantity in use becomes
slow in action.
For really fine cold black tones the following formula by MESSRS.
ELLIOTT & SON will be found admirable:--
A
Metol 40 grains.
Soda sulphite 1 ounce.
Water 8 ounces.
B
Potassium carbonate 120 grains.
Ammonium bromide 24 "
Potassium bromide 48 "
Water 8 ounces.
The developing solution consists of equal parts of A and B.
If either of the above developers is to be used, the exposure is to
be kept down as compared with the exposure to be followed by
developers intended for very warm tones.
The two developers which follow next, require about the same
exposure as the two already formulated. "Ortol" is a reducing agent
quite lately introduced by Mr. Hauff, of Feuerbach in Germany, and
Mr. Hauff's agents in this country are Messrs. Fuerst Bros., of
London. "Ortol" gives the finest tones of the warm black type that
we have as yet come across, it is singularly free from fogging
propensity, and the tones do not easily degenerate into the greens
so apt to occur after severe over-exposure with other "black"
developers. We suggest a simple formula:--
A
Water 20 ounces.
Metabisulphite of potassium 75 grains.
Ortol 150 grains.
B
Water 20 ounces.
Soda carbonate 3-1/2 ounces.
Soda sulphite 2-1/2 ounces.
To make the developer, take one part of A, one of B, and one of
water, and to each ounce of the mixture add one and a half or two
grains of potassium bromide. The development of a properly exposed
slide will take two or three minutes, and the result will probably
be highly appreciated.
The above is worthy to stand alone as representing developers for
warm black tones, but the following works well. (Messrs. Elliott &
Son.)
A
Hydroquinone 80 grains.
Soda sulphite 1 ounce.
Potassium bromide 15 grains.
Water 10 ounces.
B
Caustic soda 80 grains.
Water 10 ozs.
The developing solution consists of equal parts of A and B, and the
plate may be fully developed in about two to three minutes.
It has already been stated that in order to obtain really warm red or
reddish tones by development, it is necessary to give very long
exposure, and to use a developer very much restrained. It is further
found that carbonate of ammonia has a considerable effect in
reddening the developed image, and so we now come to procedure based
on these lines. Carbonate of ammonia is found in commerce in the
shape of "chunks" more or less square. If one of these is pared with
a knife--unless the sample is quite fresh--the outside will be found
to be a soft amorphous powder, the inside a clear, very hard crystal;
the clear crystal is in development an "accelerator," though a very
weak one, the outside substance is a restrainer. Probably both the
inside--sesquicarbonate--and the outside--bicarbonate--are useful,
and the best plan is to make a ten per cent. solution of the
substance as obtained from a good chemist--not druggist. Of this
solution one grain of the salt is represented by ten minims. If now
we take an ounce of A, and one of B of the last formula, and if we
add to the ounce of A 3 grains of ammonium bromide, and to the ounce
of B 3 grains of ammonium carbonate, and if we have given a proper
exposure and develop with equal parts of the A and B modified as
above, we shall get a slide of rich chocolate colour; and if we
double the proportions of carbonate and bromide, and expose still
longer, we shall get a slide still ruddier in tone, even to red. But
there is always danger of fog, and of clogged shadows, and this must
be reckoned with. There is a more certain and less dangerous way of
getting handsome tones, which shall be described presently.
Gelatine slides are always fixed in hyposulphite of soda, about one
part by weight to six parts of water; after this they must be well
washed, say five minutes under a good rose tap, or in many changes
of water in a dish for an hour, and every slide should be treated
with a saturated solution of potash alum, of which each pint should
contain a dram of hydrochloric acid.
Very many, if not most, slides are all the better for just a touch
of a "reducer" such as follows:--The ordinary "hypo." solution is
weakened with about four times its measure of water, and the plate
is soaked for a minute in this. A few drops of a ten per cent.
solution of potassium ferricyanide are put into the measure, and the
hypo. mixed with it, and the whole allowed to work on the plate for
a short time, carefully watched. Of course a weak slide must not be
thus treated, but it is often a good plan to develop slides to such
a point that they will permit of this treatment.
On the other hand it is often advisable to keep a slide thin in
development, for instance, when the negative wants pluck, and
intensification is indicated; or when we wish a good warm tone after
a "black" developer such as our metol formula: a good average
treatment is as follows:--
Take half an ounce each of ammonium chloride and mercury bichloride
and dissolve in 16 ounces of water, soak the slide in this till it
is bleached. Wash well and treat with weak liquid ammonia, or a
solution of soda sulphite, or of metabisulphite of potash, or fresh
lime water. This will strengthen the slide and give it in most cases
a fine rich colour. It is important to let these solutions act
thoroughly, and not to stop the action half-way. The writer
considers this the best and safest way to obtain warm tones, the
reader may find out for himself which of these solutions produces
the tones he chiefly affects.
Crystal varnish is _not_ wasted even on a gelatine slide.
In conclusion, it must be realized that the screen-image is a
greatly enlarged edition of the slide-image; any small defect on the
slide is a huge one on the screen. Consequently the slide-maker must
sedulously cultivate cleanliness and manipulative care.
_Andrew Pringle._
[Illustration: Fishing Smacks. W. Thomas. ]
_How to make Enlargements._
[Illustration]
Enlargements may be made by daylight, or by artificial light, and
there are two methods of producing them, namely, by enlarging direct
from the negative on to a sheet of bromide paper; or by first making
a small transparency, and from that producing an enlarged negative
upon a slow dry plate. The first is the method usually adopted by
amateurs, probably because the necessary operations are fewer, and
perhaps more simple. The second plan, however, possesses the
advantage that the prints may be made by any process, be it carbon,
platinum, or silver, and thus a great variety of effect obtained.
The first point however that the reader must decide is whether he
will work by artificial light or by daylight. Each may be said to
possess certain advantages, and with many the question resolves
itself into one of personal convenience. Artificial light is, or
should be, fairly constant in intensity, and if adopted there will
probably be less waste of material through miscalculation of
exposure. But if the source of light employed be other than a mixed
jet, or the arc-light, if in fact it be of low intensity, negatives
of a somewhat delicate type will be required in order to produce
enlargements of the highest excellence. If the negatives are dense
and strong, illuminants of low intensity, like oil or gas, do not
possess sufficient penetration to duly register the denser portions
of the negative, and the enlargements so made are apt to be
deficient in half-tone, and hard. With well-graded negatives of
suitable quality, however, most excellent enlargements may be
produced by artificial light. When artificial light is used work may
be carried on at any time of day or night, in winter or summer.
Those who adopt the daylight plan will, of course, be subjected to
greater restrictions, at any rate, during the winter months, but
amateurs who take a real interest in the work will do well to adopt
the writer's plan, and provide themselves with apparatus for each
method of working.
ENLARGING BY DAYLIGHT.
There are two ways of enlarging by daylight. The first involves the
exclusion of all actinic light from a room except that which passes
through the negative. The alternative method of working is to employ
an ordinary enlarging camera, such as are made by Middlemiss, or
Lancaster. It is desirable, but not necessary, if the first plan be
adopted, to secure the exclusive use of a room. One with a northerly
aspect should be chosen, for if sunlight falls upon the window
shadows will at some period of the day fall upon the negative, and
produce unevenly lighted enlargements. An upper room will be most
suitable, and, if the light be a northern one, and there are no
trees or buildings to obstruct the view, a reflector may be
dispensed with. If external objects intervene, however, one must be
employed. It should be fixed outside the window-sill, at an angle of
45°, and should be capable of adjustment. Let it be _the full width
of the window_, and _securely fixed_ for obvious reasons. A
plate-glass mirror is effective, but expensive. A large drawing
board painted dead white also answers well, but should not be left
outside exposed to the weather.
[Illustration: Fig. 1.]
[Illustration: side view ditto]
Provision for excluding the light from the room is best secured by
making a wooden frame large enough to fit closely against the window
frame. Upon this a piece of stout calico should be tightly strained
and secured with tacks. It should then be sized, and when dry will
be as tight as a drum; it must then be covered with two thicknesses
of stout brown paper pasted on. The frame is shown complete in Fig.
1. Now at AA. BB. screw two strips of wood, the distance apart
must be regulated by the size of the negatives to be enlarged. The
ordinary camera is intended to be used as the enlarging camera, and
the distance from C. to C. should be just equal to the size of the
back portion of the camera. On the lower rail BB screw a piece of 9
in. board to form a shelf or support D. for the enlarging camera.
Make a frame E. of 1/2 in. wood 1 in. deep, the same size as the
back of the camera, and screw to the shelf and top rail AA. Now
carefully cut away the brown paper and calico from the inside of
this frame, at the part marked H. and paste strips of brown paper
round it so as to prevent any light passing except through the
opening H. A strip of felt should be tacked all round the large
frame to prevent any light from creeping in between it and the
window frame. A couple of turn buttons will keep it in position. A
_firm_ table should be placed against the window close up to the
wall to form a support for the enlarging easel. Now a little care
must be taken in fitting up this portion of the apparatus, and it is
better to have something more exact than the propped-up drawing
board or printing frame, which is sometimes recommended. Get a
carpenter to run out two V shaped rails as shown in Fig. 2 at CC.
They should be about the length of the table, and screwed down upon
it. Procure a cheap drawing board about 15 x 12, and to the under
side affix two pieces of wood with V shaped grooves corresponding in
angle to the rails. This forms the base of the easel AA. Make a
frame 22 x 20, or rather larger than the biggest enlargement that it
is desired to produce. It should be constructed of 1/2 in. wood, and
be 2 in. deep. It is shown in Fig. 2 at 1 DDDD. Now make, or get
made, a set of carriers EE, the largest of which should just fit
into the frame. Narrow fillets of wood screwed each side will afford
a rise and fall adjustment, and a thumb screw at G will fix the
carrier in any desired position. To obtain the cross-movement screw
the frame DDDD to a piece of inch board 5 in. wide HH. Place this
exactly in the centre of the base board, and screw fillets II of 1
in. wood to each side. This will afford a cross motion, and a thumb
screw at J will fix the carrier frame when the necessary adjustment
has been made.
[Illustration: Fig. 2.]
In setting up an enlarging apparatus, whether it be for day or
artificial light, it is absolutely essential to preserve the
parallelism of its various parts, otherwise it will be impossible to
produce sharp or evenly defined enlargements, and for this reason I
have described somewhat fully the construction of a suitable easel.
I may add that it will serve equally well for either daylight or
artificial illumination, and I strongly advise the reader to
construct, or have constructed, an easel on the lines I have laid
down. With it either direct enlargements on paper can be produced,
or plates may be used and enlarged negatives made. The easiest way
of holding the paper during exposure is to procure two sheets of
clear glass, patent plate is most suitable, sandwich the bromide
paper between them, and secure with two strong bands of elastic. The
complete apparatus in position for working is shown at Fig. 3.
[Illustration: Fig. 3.]
[Illustration: Fig. 4.]
The second method of enlarging by daylight is by employing an
ordinary enlarging camera. The same conditions as to lighting, etc.,
should be sought for, and the most convenient way of working will be
to tilt the camera at such an angle as that the negative receives
unobstructed illumination from the sky. A reflector in this case
will not be necessary, but a piece of very finely ground glass
should be placed about an inch in front of the negative in order to
soften and diffuse the light. This method of working is shown in
Fig. 4.
ENLARGING BY ARTIFICIAL LIGHT.
Before describing the actual process of making an enlargement it
will be well to deal with the alternative method of working, namely,
by artificial light, as the manipulations of the sensitive material
used are the same in either case. Practically the most satisfactory
way of working by the latter method is to use an enlarging lantern
properly fitted with a condenser. The general principles of such an
apparatus are identical with those which obtain in an ordinary
optical lantern. Methods which dispense with the use of a condenser
are more or less unsatisfactory, and should be avoided. In the space
at the disposal of the writer it is not possible to give directions
for the construction of an enlarging lantern, but those who may
desire to make their own, will find full instructions and working
drawings in "[6]Practical Enlarging."
[6] A Iliffe & Son.
[Illustration: Fig. 5.]
Enlarging lanterns of excellent quality are obtainable commercially,
but for the guidance of the uninitiated it may be useful to refer a
little in detail to one or two important points with regard to their
construction. The condenser will first claim attention. The ordinary
pattern consists of two plano-convex lenses mounted as shown in
section at Fig. 5. This answers fairly well with the smaller sizes,
but when the diameter of the condenser is large, a good deal of
light may be lost. The interposition of a small meniscus or
plano-convex lens, in the manner first suggested by the late J.
Traill Taylor, and shown in Fig. 6, will be found a great
improvement. Its proper position will be at the point where the
divergent cone of rays proceeding from it just covers the large
condenser. In our own practice we always place a diffusing screen of
very finely-ground glass in front of the condenser at EE The
diameter of the condenser is governed by the size of the negatives
to be enlarged, it must be of sufficient size to include the longer
sides of the plate within its circumference without cutting the
corners. If it is much larger than this, an unnecessary loss of
light will occur, because only that which passes through the
negative can be utilized.
[Illustration: Fig. 6.]
THE ILLUMINANT.
The smaller and more intense the light, the nearer we approach to
the ideal projection illuminant, and the better will be the
definition of our enlargements. The arc light most nearly fulfils
the desired conditions, and if it be available it should certainly
be employed. Next in point of utility comes the limelight,
preferably in the form of the mixed jet, and those who understand
its manipulation are recommended to adopt it, but the majority of
amateurs will probably find it more convenient to use either
incandescent gaslight or an oil-lamp. Parallel wick-lamps should be
avoided on account of the unequal illumination they produce, and if
oil must be used a good circular wick burner will be found more
suitable. Where house-gas is available the incandescent gaslight is
however much to be preferred. The light is perhaps not so powerful
as that given by a really good parallel wick-lamp, but it is far
more actinic and penetrating. The writer has used this light with
great satisfaction, and therefore has no hesitation in recommending
it. Some workers have been troubled by the appearance of an image of
the mantle on the screen, but this can usually be got rid of by a
suitable adjustment of the lenses and the light, and in any case by
the interposition of a piece of ground glass between condenser and
negative.
THE CHOICE OF THE LENS.