PHOTOGRAPHING ON WOOD. 227 



in producing good illustrations is that of the artist, but if 

 the picture is put upon the wood the remainder of the work 

 is cheaply and expeditiously performed. One way of doing 

 this is to transfer an autotype carbon positive to the pre- 

 pared wood-block ; but to produce good pictures upon 

 wood it is better to employ the wet collodion process. 



A slightly over-developed positive is produced upon glass 

 in the ordinary way, being developed with an iron developer, 

 and the film transferred to the wood-block in the following 

 manner : The block is first to be coated with a gelatine 

 solution made by soaking i oz. of Nelson's gelatine in 

 19 oz. of water for twelve hours, dissolving with heat and 

 stirring in a solution of 20 grains of chrome alum in 

 i oz. of water. When thoroughly incorporated, add suffi- 

 cient lampblack to form an even black coating upon the 

 wood. 



If the block be first coated, it will be dry and ready to 

 receive the film by the time the operator has proceeded 

 thus far. The positive having been taken, developed, and 

 fixed, a piece of gummed paper is " squeezed " to the wet 

 film, which must then be stripped off the glass. The paper 

 and film may now be trimmed with the scissors, and 

 brought into contact under water with the prepared block, 

 gently squeezed to remove air and water, and set aside 

 for a while, so that the two films may become amalga- 

 mated. After a short time the block is soaked in tepid 

 water to remove the gummed paper, and after drying is 

 ready for the engraver. Many of the illustrations in this 

 work have been prepared by this process, and it is here 

 recommended to all who may read papers before the 

 members of the various societies with which they may be 

 connected. 



In the preparation of transparencies for the lantern, it 

 is necessary first of all to secure a good and sharp nega- 



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