[Ill.u.s.tration]
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 pa.s.ses 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-gla.s.s 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.
[Ill.u.s.tration: Fig. 1.]
[Ill.u.s.tration: 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 pa.s.sing 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 b.u.t.tons 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.
[Ill.u.s.tration: 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 gla.s.s, 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.
[Ill.u.s.tration: Fig. 3.]
[Ill.u.s.tration: 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 un.o.bstructed illumination from the sky. A reflector in this case will not be necessary, but a piece of very finely ground gla.s.s 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 s.p.a.ce 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.
[Ill.u.s.tration: 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 gla.s.s 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 circ.u.mference without cutting the corners. If it is much larger than this, an unnecessary loss of light will occur, because only that which pa.s.ses through the negative can be utilized.
[Ill.u.s.tration: 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 gla.s.s between condenser and negative.
THE CHOICE OF THE LENS.
It is commonly stated that the lens with which the original negative was taken will serve equally well to enlarge it, and in the abstract the statement is perhaps not inaccurate. But a.s.suming that a lens of a focus equal to about 1-1/4 times the base of the plate has been used, it will be found that better results, both in regard to definition and equality of illumination, will be obtained by subst.i.tuting a lens of rather longer focus, for example a half-plate lens for enlarging from quarter-plate negatives. This, although applying to both methods of working is particularly desirable when enlarging by artificial light, for an objective of small diameter and short focus cannot possibly pick up or receive the whole of the cone of rays proceeding from the condenser. A reference to Figs. 7 and 8 will explain why this is so. In Fig. 7 we see what happens when a lens of too short a focus is used, but when one of longer focus is subst.i.tuted, the whole of the cone of rays pa.s.ses through and is utilized (Fig. 8). In selecting a lens one should be chosen which has a sufficiently large diameter to permit the apex of the cone of rays from the condenser to pa.s.s through. This point will, of course, vary with the degree of amplification, and in order to obtain the best results optically, the distance of the light from the condenser must be carefully adjusted in every case, and a clear, evenly lighted disc obtained before inserting the negative to be enlarged.
[Ill.u.s.tration: Fig. 7.]
[Ill.u.s.tration: Fig. 8.]
With regard to the type of lens, one of the rapid rectilinear form will answer well. A portrait lens is often used on account of the brilliancy of image, but although it answers well for enlarging portraits, the roundness of its field makes it less suitable for landscapes unless it is considerably stopped down. If the very finest results as regards definition are required, then one of the now numerous flat-field lenses should be used. The writer can from practical experience speak well of the Ross-Goerz and the Cooke lens. The latter is perhaps preferable for working with artificial light on account of the larger diameter of the back lens. Wide-angle lenses, on account of their small aperture and short focus, are not suitable for use with a condenser, both for the reasons given, and on account of the difficulty in focussing owing to the small amount of light transmitted. When daylight is used, however, there is less objection to their employment.
[Ill.u.s.tration: Fig. 9.]
Before leaving this part of the subject it should be noted that in regard to preserving the parallelism of its parts the same care in erecting and fitting up the enlarging lantern must be observed, as was insisted upon in the description of the apparatus for daylight.
It will be found convenient, therefore, to mount the lantern on a base similar to that upon which the easel rests, so that both may move on the same rails. The easel described for daylight enlarging will serve equally well for working by artificial light. The complete apparatus is shown at Fig. 9, which is a reproduction from a photograph of the apparatus constructed and used by the writer.
THE NEGATIVE.
In general practice one may find it necessary at times to enlarge from negatives of very dissimilar types, but there is no reason, when the negatives are to be produced with the special object of subsequently making enlargements from them, why care should not be taken to make them of a suitable character. Thin delicate negatives should be enlarged by artificial light; dense, strong ones by daylight. If the negatives are very strong it will be difficult to produce soft and well-graded enlargements with a weak illuminant, the light not being sufficiently intense to properly penetrate the high-lights. A soft and clear negative, with good gradation, fully exposed, and neither exhibiting patches of clear gla.s.s shadow devoid of detail, nor of hard impenetrable high-light, will be found most suitable. Fog should be avoided, as also should the yellow stain produced by pyro when improperly used. Not that the pyro developer is unsuitable, for if sufficient sulphite is used, and the quant.i.ty of pyro kept down, negatives of very beautiful quality for enlarging purposes may be produced. Great care should be taken to avoid bubbles, stains, scratches, or any kind of mechanical defects, as such when enlarged become painfully obtrusive, and spoil the effect of the best work. It will be found a good plan to bind the edge of the negative before enlarging it with a strip of lantern slide binding, so as to cover the clear gla.s.s rebate mark. If this be omitted the margins of the enlargement may become fogged by the lateral spreading action of the light. No hand-work should be attempted on the original negative, for any such treatment will become painfully apparent in the enlargement. If retouching be deemed necessary, it should in the case of a direct enlargement be executed upon the print itself, or upon the enlarged negative or preferably upon the enlarged transparency, when that method of reproduction has been adopted.
DIRECT ENLARGEMENTS.
The following concise instructions for enlarging upon bromide paper will apply equally to the daylight or artificial light methods of working. In the first case the negative is placed in the dark slide of the camera, both shutters being drawn fully out. The camera is then put upon the shelf close up against the opening in the shutter, as shown in Fig. 3, any light creeping in between shutter and camera being blocked out with the focussing cloth. If the enlarging lantern is used the negative will be placed in the carrier, just in the same way as a lantern slide, with the film side towards the enlarging lens. Now the first difficulty that will be experienced will be to get the enlarged image of the required size. It will be well to content ourselves at the outset with a moderate degree of enlargement, say from 1/4 plate to 12 10, and when proficiency is acquired, larger sizes can be attempted. At first we shall probably not succeed in getting any image at all. In adjusting the various parts of the apparatus we shall find the work easier if we remember that the nearer we place the lens to the negative the further will it be necessary to move the easel from the lens, and the greater will be the enlargement. A useful table of enlargements will be found in the "British Journal Almanac," showing the distance of lens from negative, and negative from paper, for almost any required degree of amplification.
Now it will be found much easier to focus the enlarged image by looking at it through a piece of finely ground gla.s.s, than by receiving it on a piece of card or paper, and the adoption of the easel plan of focussing previously described will enable this to be done. The ground surface of the gla.s.s (which must be of the same thickness as the piece behind which the paper is to be exposed) should be away from the lens and towards the person focussing, when it is placed in the carrier of the easel, it being retained in position with the spring S., Fig. 2. Focussing must be carefully performed, and is effected by sliding the easel to and fro upon the runners, and which should have been previously rubbed with blacklead.
Bromide paper is made in several varieties, such as smooth, rough, snow-enamel, cream crayon, etc., and is put up either in tubes, or packed flat. The latter is decidedly the more convenient, it being somewhat difficult to take the curl out of paper that has been rolled. The choice of paper is a matter of taste; for landscape work the rough paper or the cream crayon will perhaps be found most suitable. For finer work, and some cla.s.ses of portraiture the enamel will prove effective. Rough paper is better for strong broad effects, smooth for more delicate work and the rendering of fine detail. The coated side may be distinguished by its tendency to curl inwards. The easiest way of exposing it is to procure two pieces of patent plate gla.s.s of the same thickness as the focussing gla.s.s, sandwich the sheet of paper between the two, and secure with strong elastic bands. This will hold it quite flat during exposure, and will not disturb the actinism of the lens or impair the definition of the enlargement.
DEVELOPMENT.
This part of the work of producing an enlargement will only be lightly dealt with, as the subject is fully treated elsewhere in this volume. The writer prefers the ferrous-oxalate developer for bromide enlargements to any of the more recently introduced developers, but as it requires more skill and judgment to employ it with complete success, beginners may find it better to use amidol or metol, either of which when properly used gives excellent results.
Hydrokinone we do not recommend for this purpose owing to its tendency to give rusty blacks in the event of over-exposure, or undue hardness if it has been too short. With amidol a pure delicate black is easily obtainable, and it is moreover a very simple developer to use. Our own plan is to employ a weak solution and give a full exposure, and by these means we find no difficulty in obtaining good gradation and pure blacks. The dish used for development must not be used for other developers or stains will probably occur. Although a quick appearance of the image is usually a characteristic of amidol, no trouble will be experienced when the developer is used in the way we advise, for the picture will be found to develop slowly and regularly, and gradually grow in strength. Quick development by this method would be an indication of over-exposure. A correctly exposed enlargement should take about ten minutes to develop. One stock solution only is necessary. It will keep indefinitely.
Sulphite of soda 1 ounce.
Citric acid 20 grains.
Distilled water 40 ounces.
Pota.s.sium bromide 15 grains.
To each ounce of the above add, just before using, three grains of dry amidol. The exposure must be accurately timed. It is, however, impossible to give useful information on this head, unless such varying factors as the rapidity of the paper, the intensity of the light, the aperture of the lens, and the degree of enlargement are known. The best plan is to cut one of the sheets of bromide paper into twelve strips, and on these make several test exposures, carefully noting the duration of each. It is better (at any rate for a beginner) not to vary the const.i.tuents or strength of the developer, but to increase or diminish the exposure until a good result in colour and tonality is obtained. By entering full details relating to the production of a successful enlargement in a notebook, great exact.i.tude in working will be obtained, and there need be little or no waste of material when additional enlargements have to be made from the same negatives at a future time.
[Ill.u.s.tration: DRIFTING STORM CLOUDS. W. THOMAS.]
A gla.s.s dish, though expensive, is very suitable for developing, for being flat-bottomed a minimum of solution can be used, and moreover if the dish should be dirty, the fact is at once apparent. The exposed paper should be soaked in water for a few minutes until uniformly wetted, and any air-bells removed with a camel-hair brush.
The water is then poured off, and the developer applied in an even wave, so that the whole of the paper is covered uniformly and quickly. The image will appear slowly, and gradually gain in detail.