A NEW PHOTOGRAPHIC PROCESS. 



443 



This is a very simple operation, consisting merely in adding to the col- 

 lodion layer firm and transparent substances, till the cliche attains the 

 proper consistence. To this end, we prepare a normal collodion of the 

 following composition : 



Gun-cotton 25 grammes. 



Sulphuric ether litre. 



Alcohol of 40 i " 



Lay the proof on a plate of glass, having first turned up the edges 

 all round, so that the liquids to be poured upon it shall not overflow. 

 On the collodion layer containing the image pour the normal collodion, 

 beginning at one of the corners of the proof most remote from the 

 operator. Then incline it slightly, so as to cause the liquid to flow ; and, 

 after the entire surface has been covered, the excess of liquid, if any 

 there be, is poured back into the bottle. Then the cliche is laid flat in 

 a roomy box, or in any other place where it will be sheltered from dust, 



and left for a few hours to dry. "When fully dried, or when it is no 

 longer sticky to the touch, we again, in the same way as before, pour 

 over the layer of -normal collodion a layer of caoutchouc dissolved in 

 benzine. When this has become dry, we apply a second layer of nor- 

 mal collodion, then caoutchouc again, and, lastly, a final layer of nor- 

 mal collodion. 



