116 



3. Note on a Method of procuring very rapid Photographs 

 (with Specimens). By John Stuart, Esq. 



The following method of takuig collodion portraits and views, is 

 so easy in manipulation, and so rapid in its results, that it is worthy 

 of the notice of every lover of photography. By means of an ap- 

 paratus adjusted to the lens of the camera, so as to open and close it 

 instantaneously, views can be taken with sufficient rapidity to deli- 

 neate vehicles in motion, assemblies of people, and even the waves 

 of the sea. 



It also produces a picture combining both the positive and nega- 

 tive on the same plate ; the positive being shewn by a reflected, 

 and the negative by a transmitted light. Copies on paper can be 

 thrown off from these plates to any extent ; but this is a difficult 

 operation, as any daylight, unless very carefully subdued, proves too 

 strong. The process is as follows : — A plate of glass perfectly clean 

 on the surface, and free from moisture, is coated with collodion, made 

 as under. It is then plunged into a bath of nitrate of silver in so- 

 lution (distilled water), 45 grs. to the oz. for sunlight, (100 grs. to 

 the oz. for portraits to he taken instantaneously in a rooni), and al- 

 lowed to remain till an oily appeai'ance on the plate disappears. The 

 plate is then fit for the camera, and will remain sensitive for twelve 

 hours, or probably longer. After the view is taken, develop the 

 picture with a solution of the sulphate of iron (20 grs. to the oz.) 

 slightly heated, and fix it (after washing) with a saturated solution 

 of hyposulphate of soda. The plate when dry, must be kept some 

 days, and then varnished with a very thin solution of Canada varnish 

 in spirits of turpentine. Previous to varnishing, the picture should 

 be brushed over with a camel-hair brush, which adds much to its 

 beauty and clearness. In a very dull light (but out of doors), the 

 above proportion, 45 grs. nitrate silver, will take portraits and views, 

 under ten seconds most distinctly, and unless the opening and shut- 

 tine of the camera be very quick, better pictures can be produced 

 thus than those taken instantaneously in strong sunlight. The col- 

 lodion found best to suit this process is made as under. — B^weight 

 sixty parts of pounded nitre, forty of rectified sulphuric acid, and two 

 of sea island cotton. The cotton must remain three minutes in the 

 mixture, and then be dried and dissolved in ether along with as much 



