free from color.

The negative can then be replaced, and no further adjustment will be needed
for any further reproduction of the same size.

There is one point that requires attention: The lens used in the camera
should be a doublet of about 6 inch focus (in reproducing 81/2 x 61/2 or
smaller sizes), and the stop used must not be a very small one, not less
than 1/2 inch diameter. If a smaller stop is used, an even disk of light is
not obtained, but ample definition is obtainable with the size stop
mentioned.

In the arrangement described, a single lens is used for the condenser, not
because it is better than a double one, as is general for such purposes,
but because it is quite sufficient for the purpose. Of course, a large
condenser is both expensive and cumbersome. There is, therefore, no
advantage in using a combination if a single lens will answer.

In reproducing lantern pictures from half-plate negatives, the time
required on my lantern plates is from two to four minutes, using 6 inch
condenser. For whole plate negatives, from two to six minutes with a 9 inch
condenser. In working in this way it is easy to be developing one picture
while exposing another.

The condenser must be of such a size that it will cover the plate from
corner to corner. The best part of an 81/2 x 61/2 negative will be covered by a
9 inch condenser, and a 61/2 x 43/4 by a 6 inch condenser.

With this arrangement it will be easy to reproduce from half or whole plate
negatives or any intermediate sizes quite independently of daylight.

* * * * *

EXPERIMENTS IN TONING GELATINO-CHLORIDE PAPER.

From the _Photographic News_ we take the following: The use of paper coated
with a gelatino-citro-chloride emulsion in place of albumenized paper
appears to be becoming daily more common. Successful toning has generally
been the difficulty with such paper, the alkaline baths commonly in use
with albumenized having proved unsuitable for toning this paper. On the
whole, the bath that has given the best results is one containing, in
addition to gold, a small quantity of hypo and a considerable quantity of
sulphocyanide of ammonium. Such a bath tones very rapidly, and gives most
pleasing colors. It appears, moreover, to be impossible to overtone the
citro-chloro emulsion paper with it in the sense that it is possible to
overtone prints on albumenized paper with the ordinary alkaline bath. That
is to say, it i