DEVELOPMENT OF THE STEREOSCOPIC :NEGATIVE.
The development of stereoscopic plates being similar in treatment to any ordinary dry plate, it is only necessary to say that uniformity, when two separate plates are in use, should be aimed at. Over-develop ment is to be preferred to under-develop ment. A thin negative yields far better prints for stereoscopic pictures than a dense one. A special point to be remem bered in the development of stereoscopic negatives is to obtain as much detail as possible in the darker portions of the pictures before the high lights have be come too dense. To ensure this, a formula containing very little pyrogallic acid should be used ; failing this, eikonogen, amidol, or metol will be found to give satisfactory results.
EcrocenING STEREOSCOPIC NEGATIVES.
It is next to impossible to retouch two negatives forming a stereoscopic pair with absolute equality, and, unless every touch applied to the left negative is accurately duplicated in the right negative, the effect in the stereoscope when the resulting prints are combined will be anything but satisfactory. White spots, resulting from
the retouched negatives, will appear as floating specks of dust in mid-air. For this reason it is advisable to omit re touching altogether, with the exception of blemishes that may occur in the darker portions of the composition, which may be dismissed by careful treatment. The best method of doing this is to spot the prints after they are mounted. Any of the commercial "printing-out papers" are suitable for stereoscopic pictures, also enamel surface bromide paper, which will prove useful if circumstances prevent the use of daylight for printing. A dark print is preferable to a weak one, as the stereo scope enables the eyes to pick out details even in the shadows which would be over looked in a single print of equal depth unassisted by glasses.