18 



and half a drachm mucilage gum arable. When dry, the paper is 

 drawn over the surface of a solution of sixty grains of nitrate silver 

 in one ounce of distilled water. Allowed to dry in the dark, the 

 paper is now fit for use, is of a pure white, retains its colour, and 

 may be preserved for a considerable time in a portfolio, until 

 wanted for use. 



The preparation of this paper is by no means difficult, but 

 requires much care and attention. The solutions must be applied 

 very equally over the paper, which should be immediately hung 

 upon a frame or clothes' horse to dry. Extreme care must be 

 taken that the paper be not exposed to light, after the nitrate of 

 silver solution has been applied, until required for use. Many of 

 the disappointments experienced by the experimenters on the 

 Energiatype are occasioned by a neglect of this precaution ; as, 

 although no apparent effect may have been produced by the 

 exposure, the clearness of the subsequent picture will be seriously 

 injured. The succinic acid must also be very pure. In the general 

 way it will be found more convenient, and perhaps economical, 

 to purchase the paper ready prepared. We shall now briefly 

 describe the method of applying the Energiatype to the different 

 purposes for which it is best adapted, premising that the varying 

 circumstances of time, place, and light, will render necessary such 

 modifications of the following directions as the experience of the 

 operator may suggest. As a general rule, an open situation, sun- 

 shine, and, if possible, the morning sun should be preferred, as the 

 image is sharper, and the colour produced more intense, and less 

 effected by the subsequent fixing process. 



NEGATIVE PICTURES. 



IN THE CAMERA. Fora building, an exposure of half a minute 

 in strong sunshine is usually sufficient ; for a portrait, which can 

 only be taken in the shade, two or three minutes is required. 

 Directions for placing the camera, sitter, etc., etc. will be found 

 under the Calotype process, at page 13. 



Exact copies of prints, feathers, leaves, etc. may be taken, by 

 exposing them to the light in the copy ing -frame, described, p. 7, 

 until the margin of the prepared paper, which should be left 

 uncovered, begins to turn very slightly. If the object to be copied 

 be thick, the paper must be allowed to assume a darker tint, or the 

 light will not have penetrated it. 



