On Sun Pictures. 4538 
tinted on the prepared side of a delicate straw colour. They 
will keep for any length of time without being affected by 
the light, care being taken never to touch the prepared 
surface with the fingers. 
2nd Operation—The Sensitive Solution. 
The following process must be performed by the light of 
a candle, or if by daylight it must be passed through a 
yellow medium, and the chemicals must be carefully guarded 
from the sun-light. 
Take 25 grains nitrate of silver, 1} drachms acetic acid, 
4 an ounce of distilled water, mix in a glass bottle, then 
make a saturated solution of Gallic acid with distilled water 
in another bottle ; when required for use mix 15 drops of the 
aceto-nitrate solution, with 80 drops of saturated Gallic acid, 
in 6 drachms of distilled water. Brush this into the prepared 
side of the paper, fastened on a board as before, with a clean 
brush, and let it remain for about a minute, the board being 
inclined. Then place the paper between folds of blotting- 
paper until nearly dry. It is now fit to be placed in the 
camera; and it is better to use it as soon as possible after 
the above preparation :—this last solution will not keep 
above a day. 
8rd Operation—In the Camera. 
Place the paper prepared as above, and carefully secured 
from the daylight, with its face to the glass of the frame of 
the camera; then slide the frame into the camera, 
The focus of the object must previously have been care- 
fully adjusted on the ground glass of the camera. ‘The tne 
of exposure can only be learned by practice; 
> It will vary 
with the intensity of the chemical light on the day or season 
