The Apparatus Photography 102

Fig. 59.

Selection Of Subject

With the exception of copying from a plane surface, practically all ordinary subjects for photography are within the scope of the stereographer. Landscape, seascape, architecture, interiors, still life, flowers, portraits, figure studies - all lend themselves to stereoscopic treatment. Landscape and seascape of the "open" variety, however, should be avoided : a strong foreground is essential to the making of a good stereograph, and the most pleasing effect is obtained when the points of interest are situated in several different planes, and form resting-places for the eye from foreground to distance.

Exposure And Development

The good old rule of exposing for the shadows should be the stenographer's constant guide. Detail is wanted in every part of the picture, especially in the foreground; the exposure must therefore be ample. Under-exposure, always a bad fault, is trebly so in stereography, but a little over-exposure will not matter. The great thing is to ensure good detail everywhere. The lenses should be stopped down sufficiently to give full depth of focus and sharpness; no fuzziness or diffusion of focus is admissible. This rule should only be relaxed when circumstances demand an extremely rapid exposure, necessitating the use of a large aperture. In that case, special care must be taken that the actual subject of the photograph is in sharp focus.

Though exposure should be for the shadows, development should be for the high lights. Over-development must be avoided as carefully as under-exposure. Softness rather than pluckiness should characterise the stereoscopic negative, and the developer should be chosen with this in view. Whatever developer is used, it should contain only the minimum of bromide, and this should not be increased except in cases of known over-exposure.

Finishing The Negative

If by accident or miscalculation a negative of "contrasty" character is produced, reduction by persulphate of ammonium will usually effect a great improvement, unless the error is that of great under-exposure in which case destruction is better. It is futile to attempt to obtain a pleasing stereoscopic print from a negative that lacks detail.

There is no branch of photography in which cleanliness and careful manipulation are more important than in the production of the stereoscopic negative. Every defect is intensified in the stereoscope; slight blemishes which would be unnoticed in an ordinary photograph are brought into startling prominence. The perfect negative should always be the aim of the stereoscopic worker; there is no place in stereography for careless and slapdash methods. Pinholes and slight defects of that nature will occur, however, in spite of the best care; and every negative should be minutely examined for them. Spotting must be done with extreme delicacy, or the remedy will prove worse than the disease. The density of the deposit in which the defect exists must be matched as exactly as possible, and the spotting medium must not be allowed to trespass beyond its limits. We find a No. 0 sable brush the best spotting instrument, and Indian ink, rubbed down in a few drops of water in which a little gum arabic has been dissolved, is a good spotting medium. To prevent the spreading of the medium, the tip of the brush only should be moistened with it.

Paper Prints

For paper prints there is nothing so good as gelatino- or collodio-chloride P.O.P. All processes which increase contrast or diminish detail must be classed as unsuitable; thus we rule out bromide and gaslight papers. We have seen many stereographs on bromide paper, but not one that would not have been better on P.O.P. If gaslight printing must be resorted to, phosphate paper will be found to approximate most nearly to P.O.P. in gradation, tone, and rendering of detail. Whichever printing process is adopted, the paper should be of the glossy variety.

In making P.O.P. prints, continue the printing until the high lights have lost their whiteness. If, through undue contrast in the negative, this is not possible without clogging up the shadows, it is best to remove the print from the frame when the shadows are fully printed, and expose it boldly to the light until the white patches are slightly discoloured. The object of this "sunning down" is to prevent the snowy effect noticeable when slides of too contrasty a kind are viewed in the stereoscope.

A warm brown is, as a rule, the most suitable tone for stereographs, and care should be taken not to carry toning too far. After fixing and washing, hang the prints up to dry; the natural gloss thus retained is preferable to the mirror-like surface got by squeegeeing.

Paper Prints Photography 103

Fig. 60.

Paper Prints Photography 104

Fig. 61.

Paper Prints Photography 105

Fig. 62.

Trimming And Mounting

In a contact print from a stereoscopic negative, the picture taken by the right-hand lens is on the left hand, and vice versa. Why this is so will be seen from the following diagrams (Figs. 60-62). Let us imagine the part of Fig. 60 marked "Left" to be an object as seen from the position of the left-hand lens, and the part marked "Right" to be the same object as seen from the position of the right-hand lens. The images thrown on the plate will be inverted independently of each other, and the negative, if looked at from the back, in the position it occupied in the camera, will be as Fig. 61, where, it will be noted, the outer edges, A, B, C, D, have become adjacent. On turning the negative right-way up, and making a contact print from it, we obtain the result shown in Fig. 62. Now, as it is necessary that the right-eye picture should be seen by the right eye, and the left by the left eye, the two sections of the print must be transposed before mounting. If this be neglected, the image obtained in the stereoscope will be pseudoscopic - turned inside out, as it were, the distance taking the place of the foreground, and the foreground receding into the distance. To guard against this error, every print, before trimming is commenced, should be lightly marked on the back with a pencil stroke as shown at A B in Fig. 63. When, later on, the print is cut into two, a portion of the pencil mark will be on each section, serving to show which edges must be outermost when the prints are mounted.