H. S. S.
PHOTOGRAPHIC CORRESPONDENCE.
Washing or not washing Collodion Pictures after developing, previous to fixing.—Since the question has been mooted I have tried both ways, and have come to the conclusion that there is very little difference in the resulting appearance of the picture. The hypo. is certainly deteriorated when no washing is adopted. I think it is best to pour off the first quantity applied into a cup kept for the purpose; this is discoloured: I then pour on more clean hypo., and let it remain till the picture clears, and pour this into another cup or bottle for future use. What was poured into the first cup may, when a sufficient quantity is obtained, be filtered, and by adding more of the salt is not useless. I pour on merely enough at first to wash off the developing fluid, and pour it off at once. The picture is cleared much sooner if the saturated hypo. solution is warmed, which I do by plunging the bottle into a pewter pint pot filled with hot water.
W. M. F.
Stereoscopic Angles (Vol. viii., pp. 109. 157.).—I perfectly agree with your correspondent Mr. T. L. Merritt (p. 109.) respecting "stereoscopic angles," having arrived at the same conclusion some months since, while at Hastings, where I produced stereoscopic pictures by moving the camera only two inches: having in one, seven houses and five bathing-machines; and in the other, five houses and eight bathing-machines. If I had separated the two pictures more, I should have had all bathing-machines in one and all houses in the other; which convinced me that nothing more is required than the width of the two eyes for all distances, or, slightly to exaggerate it, to three inches, which will produce a pleasing and natural effect: for it is quite certain that our eyes do not become wider apart as we recede from an object, and that the intention is to give a true representation of nature as seen by one person. Now, most stereoscopic pictures represent nature as it never could be seen by any one person, from the same point of view; and I feel confident that all photographers, who condescend to make stereoscopic pictures, will arrive at the same conclusion before the end of this season.
If this be correct, all difficulty is removed; for it is always advisable to take two pictures of the same prospect, in case one should not be good: and two very indifferent negatives will combine into one very good positive, when viewed by the stereoscope: thus proving the old saying, that two negatives make an affirmative.
Henry Wilkinson.
Brompton.