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Proceedings. [No. 7, kew series. 



Mr. Underwood mentioned to the meeting that he has for a con- 

 siderable period been endeavouring to make an iodizing mixture 

 for collodion, suited to the climate of Madras, and that he had 

 reason to believe he had succeeded both with positive and nega- 

 tive collodion. Collodion iodized with it whether Horn's, Thomas's, 

 Bertch, or made by himself, seemed to answer equally well. For 

 positives the collodion should be dark, for negatives lemon color. 

 The first is obtained either by keeping iodized collodion some time 

 or what appears preferable mixing old collodion with collodion 

 freshly iodized half and half, or one-third according to the age of 

 the old collodion — the guide is not to mix enough of old collodion 

 to make the film of the collodion tender. The color of freshly 

 mixed iodized negative collodion should be removed either by sil- 

 ver or zinc. Mr. Underwood states, that the unsatisfactory results 

 of collodion received from Europe is consequent upon the differ- 

 ence of the light in India. In England the shadows are light and 

 the sun shining on an object illumines it, but in this country, the 

 shadows are black and form a hard dark outline, while at the same 

 time the object illumined by the sun has a dazzling brightness, con- 

 sequently those parts are over exposed before parts in shadow are 

 depicted on the collodion plate. A sacrifice must therefore be 

 made, and the result is an unsatisfactory picture. Mr. Underwood 

 exhibited three portraits by Mr. Nicholas which were taken with 

 the collodion iodized with the mixture above mentioned. One of 

 the Lord Bishop, one of Mr. Cherry, and one of Captain Nicholas. 

 They were pronounced to be excellent portraits and very satisfac- 

 tory Photographs ; the one of the Bishop appeared to exhibit the 

 half tones in the most satisfactory manner, and the members pre- 

 sent were of opinion that the whites were excellent in all while 

 the blacks were clear, that there was a degree of brilliancy in the 

 pictures, and that the half tones were well preserved. 



A small paper positive printed from a collodion negative of 

 Christ's Church taken by Mr. Nicholas was satisfactory, as in it 

 the lights were excellent, while the parts of the building in shadow 

 were well pourtrayed. Mr. Underwood observed it was satisfac- 

 tory to learn that the end desired was considered to have been 

 attained in the pictures laid before the meeting, and stated that 



