RECENT IMPROVEMENTS IN PHOTOGRAPHY. 247 
ART. LII.— "AN ACCOUNT OF SOME RECENT IMPROVE- 
MENTS IN PHOTOGRAPHY. By H. F. Talbot, Esq. F. R. S." 
The author had originally intended, in giving an account 
of his recent experiments in photography, to have entered 
into numerous details with respect to the phenomena ob- 
served, — but finding that to follow out his plan would occupy 
considerable time, he has thought that it would be best to 
put the Society, in the first place, in possession of the princi- 
pal facts, and by so doing perhaps invite new observers into 
the field during the present favorable season for making ex- 
periments. He has, therefore, confined himself at present to 
a description of the improved Photographic method, to which 
he has given the name of Calotype, and reserves for another 
occasion all remarks on the theory of the process. 
The following is the method of obtaining the Calotype 
pictures. 
Preparation of the paper. — Take a sheet of the best writ- 
ing paper, having a smooth surface and a close and even 
texture. 
The water mark, if any, should be cut off lest it should 
injure the appearance of the picture. Dissolve one hundred 
grains of crystallized nitrate of silver in six ounces of dis- 
tilled water. Wash the paper with this solution, with a soft 
brush, on one side, and put a mark on that side whereby to 
know it again. Dry the paper cautiously at a distant fire, or 
else let it dry spontaneously in a dark room. When dry, or 
nearly so, dip it into a solution of iodide of potassium, con- 
taining five hundred grains of that salt dissolved in one pint 
of water, and let it stay two or three minutes in this solution. 
Then dip it into a vessel of water, dry it lightly with blotting 
paper, and finish drying it at a fire which will not injure it 
even if held pretty near ; or else it may be left to dry sponta- 
neously. 
