The photographic camera should form an essential part of the traveller’s outfit, as it affords the only trustworthy means of obtaining pictorial records of his journey, and it is also helpful in making the survey of a new region, delineating its contours, its geological and botanical features, and ethnographical types of race. The camera and materials necessary for a journey may be readily obtained, so designed as to minimise space and weight, and in every way so perfectly adapted to the traveller’s needs as to ensure successful results in every variety of climate, and render the operation of taking a photograph extremely simple. It is necessary, however, that the traveller should make himself master of the principles involved in the production of a successful photograph, as he will have to depend on his personal effort in exposing and developing the plate, etc. He should also acquire a knowledge of the construction of the camera, to enable him to effect slight repairs when necessary.

In selecting an outfit he must first decide upon the size of plate to be carried, and that need not exceed what is termed “half-plate,” 6½ × 4¾ inches; which is large enough for the best work. The smallest effective size for scientific work may be “quarter-plate,” 4¾ × 3¼ inches; in use in many hand-cameras. Negatives on this scale, if perfect, may be enlarged for book illustration, or printed as lantern slides. The two sizes given form a very complete outfit when extra weight may be conveniently carried.

Selecting a Camera.—The cameras should have bellows bodies of Russian leather which folds into small space, the woodwork must be well seasoned to prevent warping, or cracking under a hot sun. The framework should be metal-bound at the corners, and the camera fitted with a rising front and swing back, although the swing back is not indispensable. A reversible back (now universal) is of advantage, as it enables the operator to take vertical or horizontal views without turning the camera on its side. If the camera is fitted with a swing-front, the swing-back becomes unnecessary. The swing-front is in all ways preferable to the swing-back.

The Hand-camera.—Hand-cameras are designed to carry a dozen or more plates or films in flat sheets or in spools, so arranged inside the camera as to be changed after each exposure by simply turning a milled head, or moving a lever. Rolled films are not recommended for travellers’ use in hot and humid climates. Sir Martin Conway says: “A traveller who carries glass plates and flat films will probably bring home a larger percentage of good negatives from a long mountain journey than one who relies upon spools of films.” There can be no question about the force and accuracy of this statement. My own experience goes to prove that a camera arranged for glass plates and flat films is best.

The twin-lens hand-camera made by Ross, of New Bond Street, London, offers several advantages in its design. It is fitted with a focal-plain shutter which is in every way simple and effective. The twin lenses are of equal focal length, enabling the object to be photographed to be seen on the same scale as it will appear in the finished negative, so that just what is required may be embraced in the field. It consists of a stout body of thoroughly seasoned hardwood, not easily damaged by rough usage. The principal fittings required for adjusting the instrument are inside, protected by the outer case. The exception to this arrangement is the milled head by means of which the two lenses are focussed at the same time. The lenses are of uniform focal length, so that the image transmitted by the “finder” is a counterpart of the image which falls upon the sensitive plate. The advantage of this is that the object to be taken is seen on the finder-screen to scale exactly as it will appear in the finished photograph. By this means the operator has it in his power to place the object in the required position on the screen at the moment of exposure. This is of signal importance if the object is moving about. It must also be noted that this form of camera may be used when the operator is facing at right angles to the object to be photographed. I have frequently found that natives of foreign countries resent the liberty taken of pointing a camera at them, and fly as if they expected to be shot. The slides are each made to hold two plates, or flat films. They are strong, serviceable, and easily managed, while the body of the camera is so arranged as to carry a roll holder. The camera can also be adapted to stereoscopic work, and fitted for the use of glass plates, flat films, or rolled films.

A light tripod stand should be taken for supporting the camera when longer exposures are required than can be given in the hand. A very satisfactory compromise has been adopted by Sir W. Abney between using the camera in the hand and on a tripod. He rests the camera on top of a walking-stick when making hand exposures, with the result that he overcomes all tremor caused by pulsation, and so secures photographs full of sharp detail.

The same object is obtained by the reflex type of camera in which the image formed by the lens is thrown upon a silver-faced mirror and reflected upward to the focussing screen. Focussing can be carried out, and a moving object followed till the moment when the exposure is made. The reflex type of camera is a trifle less bulky than the twin-lens, and, of course, only one high class and expensive lens is required.

A Focussing-cloth.—This is used for keeping out the light while focussing, being thrown over the camera and the head of the operator. It is generally made of black velvet, but waterproof sheeting is much better. It should have rings sewn on to one edge, or some arrangement by which it may be attached to the camera so as not to be blown away.

Camera-stand.—There are many varieties of tripod stands, with legs either folding or sliding into a small compass. For mountainous country it is of great advantage to have a stand with telescopic legs, as they can be readily altered in length so as to stand firmly on slopes or rocky ground. The smallest size, weighing about 3 lbs., and measuring 33 in. long when closed, and standing about 4 ft. 6 in. high, is steady enough to support a 6½ × 4¾ camera without perceptible vibration in a moderate wind.

A Small Circular Cup Level, let into the wood of the camera, for levelling the camera on the tripod, is a useful addition.

Lenses.—There are many lenses in the market, and as it is impossible to do good work with an inferior lens, it is necessary to exercise great care in selecting this part of a photographic outfit. Lenses known as rectilinear or symmetrical are useful to a scientific explorer, and are well fitted for producing pictorial effect in his work.

Ordinary portrait lenses are designed specially for rapid work, and this is attained at the cost of qualities in a lens most useful to an explorer. The so-called portrait combination should therefore be avoided.

Rectilinear and symmetrical lenses give true images of objects to be photographed free from distortion, so that straight lines are reproduced as straight lines. In this way they are invaluable where accurate measurements have to be taken from photographs produced by them.

Ross’s homocentric lens is one of the most useful lenses. It has a flat field, is free from what is called “coma” and astigmatism, and is so perfectly corrected as to fit it for interior and exterior work alike. It is also a rapid hand-camera lens. The homocentric are made in series to suit all cameras. Other lenses may also be noted, viz.: c. Dallmeyer’s rapid rectilinear, including about 37°. d. Zeiss’s anastigmat, made by Ross, consists of a double front lens and a triple back lens. It is intended for portraits, groups, copying, and general outdoor work. The combinations being brought closely together, gives them great illuminating power. They have an angular aperture of from 858 to 908, and can therefore be used as wide-angle lenses when desired. In consequence of the peculiar system of correction for oblique pencils adopted in these lenses, they behave somewhat differently from the usual types with regard to the mode of compensating the effect of the resulting aberrations between centre and margin of the field. This is, of course, only possible in the case of perfectly plane objects. In all other cases—landscape, instantaneous work, or interiors—the centre should be focussed rather than objects at a distance or foreground.

Focus.—It will be sufficient to say that focal length means the distance between the diaphragm of a lens, and the ground-glass screen when the image of a distant object is seen most distinctly on the screen.

Exposure Tables.—Exposure tables are based on the focal length of a lens, in relation to the diameter of the diaphragm of a lens. Thus, if the focus is eight inches and diameter of diaphragm one inch, the relationship will be expressed by f /8 or by the uniform standard number 4, and so on, as in table. The diaphragms are so arranged for size of opening that each succeeding number requires double the exposure necessary with the one preceding it. f /11.3, for example, requires double the exposure wanted with f /8.

Such tables are useful guides to the relative duration of exposure with diaphragms of different sizes applied to the same lens. They afford no clue, however, to time of exposure to be given with any particular lens or diaphragm. This can be best ascertained by experience, as duration of exposure of a plate or film in the camera depends on the sensitiveness of the plate, the time of day, the sun, the state of the atmosphere, the nearness or distance of the object to be photographed, etc. To take an extreme case of the difference of time required to impress the plate with the image of an exterior view and that of an interior, a landscape open and well lighted may be taken in the fraction of a second, while a dimly-lighted interior with the same lens would require an hour, both being taken with plates coated with the same emulsion. The duration of exposure may be approximately estimated by using an exposure meter such as may be obtained from any photographic dealer’s. It is useful to keep an exposure record; a handy book for this purpose is published by Messrs. Burroughs & Welcome. In this book rules are set down for exposure during different months of the year and for different latitudes. These are apt to prove misleading to the amateur. The simplest method of measuring the actinic power of light in any latitude, and at any moment, is by actinometer, giving plate-speeds, focus of lens, etc. Watkins “Bee Meters” are excellent for this purpose.

Sensitive Plates or Films.—Gelatine plates are now made commercially by a large number of firms and of great excellence; they keep indefinitely before exposure, and for a long time afterwards and before development and under some circumstances (as for instantaneous pictures, portraits, and dimly-lighted interiors) will give results which could hardly be obtained at all on collodion plates. Gelatine plates are made of various degrees of sensitiveness; the slowest are best for ordinary landscape work. They are generally supplied in parcels of a dozen each, packed face to face with strips of folded paper between opposite edges. The card boxes in which they are usually packed are an insufficient protection against injury and damp. In all cases it is advisable, and for sea voyages and damp climates essential, to have each package of a dozen plates soldered down in a tin case, and afterwards packed in a light wooden box with tow or cotton wool, and the box screwed (not nailed) down. In packing them up again after exposure or after development, a good plan (due to Sir W. Abney) is to provide oneself with a number of cardboard frames exactly the size of the plates, made of strips of card about ¼ in. wide, one of which is inserted between every two plates film to film. The packages thus made up should be soldered down again, and treated with at least as much care as the original plates in packing. Should there be no available means of resoldering the boxes, it will be better to have tin boxes with the lid turned well down, the joinings to be closed by strong well-gummed paper or medical rubber strapping. It will also be well to be provided with a supply of waterproof paper, or cloth, as an additional precaution in packing and in case of emergencies.

Sensitive films in rolls or spools are made by the Kodak and other companies, and may be used successfully in their proper roll-holders when they can be kept perfectly dry in temperate climates. Flat films made by Kodak, Ltd., and others have many advantages for travellers. The celluloid of which they are made is very much lighter than glass, and in exposure and development may be treated in the same way as a glass plate. When plates can be carried, the extra weight is compensated for by greater certainty of success, and general excellence in the photographs.

How to Keep Plates and Films Dry.—When the traveller has a long journey before him, and the prospect of storing his plates and films for months both before and after exposure, it is of the greatest importance that precautions should be taken against the inroads of damp. This applies with full force when the country to be explored has a hot, humid climate. Plates and films that have absorbed moisture, causing decomposition in the sensitive gelatine coating, are frequently brought back to this country to be developed, and are the most fruitful cause of failure. The remedy is simple, but can only be applied when packing and repacking the plates. Some guarantee should be sought from makers of plates and films that they are packed perfectly dry, and that the packing used is also dry. Assuming that work has to be done in a damp climate and that the plates have been exposed in the camera and require to be repacked, they should be dried in a box containing a small quantity of chloride of calcium. The box used for drying may be also designed to carry the camera and outfit. It should have a lid with a rim of rubber padding, so that by putting the lid on and a weight on it, the box would be fairly air-tight. Stack the exposed plates, or films, in the bottom of box, so separated as to permit the passage of air between. Place a cup or saucer on the bottom of box containing chloride of calcium. (The chloride should be first dried on a piece of iron over a fire.) Put on the lid and allow the plates to remain for an hour or more. Dry all the packing materials, remove the plates from the box and repack. The chloride will have absorbed the moisture in the plates, and rendered them quite dry and safe for preserving for an indefinite length of time.

Apparatus and chemicals for development.—The development of the plates or films after exposure in the camera requires practice and experience in order to secure the best results. Instructions for development are sent out with all commercial plates or papers, but many failures would certainly result from attempting to work by these without some preliminary practice at home. As plates, &c., will keep after exposure (if well protected from damp) for 18 months, or longer if properly packed, it is not, of course, necessary to develop them en route, although if the traveller possess sufficient skill, and if ample water-supply and other facilities can be secured, it will be advantageous for many reasons to do so. On a long journey, when the temperature is not too high, use of convenient resting-places may be made to develop from time to time a few plates selected from the whole, both as tests for exposure and as proof that all the apparatus is in order. The following list comprises all that is absolutely required for developing 8 or 10 dozen gelatine plates:—Three papier-mâché dishes, two 3-ounce glass measures, three 6-ounce bottles, containing strong solutions of pyrogallic acid preserved with potassium meta-bisulphite, potassium bromide, and sodium carbonate respectively, 1 lb. hyposulphite of soda, and ¼ lb. alum, both in crystals, 4 or 5 feet of india-rubber tubing and a spring clip, to make a syphon for a water supply from a jug or can, a basin or tub to serve as a sink, a folding rack for draining the plates.

There are several convenient new developing agents in the market: Hydro-Kinone, Eikonogen, Glycin, Metol, Rodinal, and Amidol. Some of these were made and named in Germany, they are no longer procurable under their German names. English manufacturers are however making substitutes quite as good under new names, and these can be obtained from the dealers. Many of them can be obtained in compressed form.

The traveller is recommended for advanced study of photography, such works as Instructions in Photography by Sir Wm. Abney, The Science and Art of Photography by Chapman Jones, and The Manual of Photographic Exposure and Development by Alfred Watkins, which may be had from any photographic dealer’s.

The aim of the traveller-photographer should be the production of good negatives. It often requires years of study on the part of professional operators (with advantages impossible to the traveller) before thoroughly good negatives are habitually produced; and it must not be supposed that a person taking up photography for the first time, in a few hurried moments before departure on a journey, will attain other than very unsatisfactory results.

The operations necessary for taking a picture are briefly as follows:—Having selected the position from which the view is to be taken (for valuable hints as to the artistic production of pictures see Robinson’s ‘Pictorial Effect in Photography’), the tripod stand is first set up, and the head approximately levelled by means of the pocket level, altering the position or length of the legs as may be necessary. The camera is next screwed on to the stand, and the lens selected which on trial is found to include the required amount of subject. For groups or portraits a long focus lens with wide aperture, such as Dallmeyer’s “Rapid rectilinear,” 11 in. focus, should be used. The next operation is to focus the picture accurately on the ground-glass screen of the camera. The focussing-cloth is thrown over the head and the camera, so as to exclude the light as much as possible, and while looking at the inverted image on the ground glass, the milled head of the rack adjustment is turned till the image appears as sharp as possible. The camera is now turned about on its vertical axis till it exactly includes the view intended to be taken, and the screw is tightened. It may be necessary to raise or lower the front of the camera carrying the lens in order to include objects at a high or low elevation; if the vertical range of this sliding front is insufficient, the camera must be tilted; but, if this is done, care must be taken to set the focussing-screen vertical again by means of the swing back, and to readjust the focus. The full aperture of the lens should always be used for focussing, and if the image is not sharp all over the plate it will be necessary to insert a diaphragm in the lens, using the largest that will effect the required object. Having then put the cap on the lens, the hinged frame carrying the focussing-glass is turned over, and one of the slides carrying the sensitive plates is inserted in its place. The slides should be exposed as little as possible to the light, especially avoiding direct sunlight; however carefully constructed, it is difficult to make them absolutely light-tight. The shutter of the slide is then withdrawn, and the exposure made by removing the cap from the lens for time exposure, and by a spring shutter for instantaneous work. The time of exposure must be estimated according to circumstances, and it requires considerable experience to judge of it accurately. A record should be kept in a note-book of every plate exposed, giving the number, date, time, exposure, subject, &c. If the plates cannot be developed the same evening, and the slides are wanted for fresh plates, they must be packed up again, and should be numbered. This is best done by marking the number on the back with a bit of dry soap, or in the film with a lead pencil. The image on the plate after exposure is latent and invisible, and has to be developed. This is effected by pouring on the plate, laid in one of the flat dishes, a dilute solution containing pyrogallic acid, soda, and potassium bromide. The excellence of the result largely depends on the due proportion between these constituents, and here more experience is perhaps necessary than in any other part of the process. The image having been fully developed, the plate is well washed, and then immersed in a solution of alum, which hardens the film. After another thorough washing it is “fixed” by immersion in a solution of sodium hyposulphite, which dissolves out the unchanged bromide of silver, and, being once more well washed, it is finished, and must be set up in the rack to dry spontaneously. On no account must heat be applied, not even the warmth of sunlight, or the wet film will melt. When dry it must be varnished to protect the film. The printing operations are best deferred till the return home, as they would involve the carriage of a large amount of extra apparatus. It is generally best to get the printing done by a professional printer; but if the traveller prefers to print from his own negatives he will find full instructions in each packet of paper which he buys.

Colour sensitive plates are now much used and, when a yellow glass filter is placed immediately in front of, or behind, the lens, will give in the print the same variations in depth of tint which the eye sees in the landscape, or other object. The nearest to perfection among these plates are those known as Panchromatic, but they must be developed in total darkness. The subject is a large one and should be studied in the pamphlets on ‘orthochromation’ published by Kodak (Wratten Division), and Ilford, Ltd.

As regards the expense of a photographic outfit, at the present time the manufacturing trade is still very unsettled, some goods cannot be supplied, and all have been greatly increased in price. Quarter plates which used to be sold at a shilling per dozen are now about 3s. 6d. Application should be made to the dealers for current prices.

The camera, slides and lenses may be arranged to pack into a solid leather case, conveniently in the form of a knapsack, measuring about 16 in. wide, 12 in. high, and 5 in. deep. This can easily be carried on the back of one man, and is of a more convenient shape than the cases generally sold for the purpose.

The plates and other apparatus, with the exception of the knapsack and its contents, and the tripod stand, are best packed for travelling in a strong basket, which is much better than a box, being more elastic and lighter. It will weigh, when packed with the apparatus, and a gross of 7½ × 5 plates, about 60 lbs.

Photography in Natural Colours.

It is now possible for the traveller to bring home records of what he has seen in natural colours. There are two or three known methods by which this may be done, but few are available for the work of exploration. The picture obtained by the method patented by Mr. Ives and named Krōmskōp Photography is produced by three monochrome images. These have however been taken through three tinted glasses in a camera of a special kind. The images may be thrown upon a screen by means of a special lantern; the light passes through tinted glasses of colours complementary to those employed in making the negatives with the result that the picture on the screen exhibits all the varied hues of nature. The devices however are exceedingly expensive and can be satisfactorily employed only by those who thoroughly understand the apparatus and the problems which have to be solved.

Simpler processes are the Autochromic and The Paget Colour Plate process. In the Autochromic process the manufacturers coat a sheet of glass with minute specks of three colours, blue, violet green and orange, irregularly spread, and lay a coat of panchromatic emulsion on top. The photographer exposes through the glass, thus obtaining a negative. The developed silver, the negative image, is dissolved away and the silver bromide remaining is developed giving a positive image in natural colours.

In the Paget process the glass is coated with points of colour laid in a regular pattern. This is called the screen plate and is placed in the dark slide face to face with a colour-sensitive plate, and the expression is made through the screen plate. From the negative so obtained a monochrome positive plate is made, and this is bound up in contact with one of the screen plates. Some little experience is necessary to obtain correct register.

Each process has its difficulties. Most photographers consider that the Autochrome plate gives the nearest approach to natural colours, but the slides are very dense and require an intense light to show them well. The Paget plate is much more transparent and possesses the advantage that any number of positives may be made from the negative, whereas the Autochrome plate having been converted into a positive cannot be multiplied, resembling in that particular the earliest form of photography, the Daguerrotype.

None of these colour processes are suitable for photographing objects in motion. The exposures may be reckoned as from fifteen to twenty times as long as with an ordinary slow plate.