1 22 J. Waterliouse — The Application of 'Photography [No. 2, 



If the greatest simplicity in the printing operations is an object, the 

 cyanotype or other iron processes may be used. If the prints are required 

 to be permanent, the simple pigment process or the autotype may be em- 

 ployed, according as the original is in line or shaded. 



If a large number of copies are required, then it will be more advisable 

 to employ one of the photo-mechanical processes. The choice will depend 

 much upon the nature and importance of the subject. As a general rule, 

 in cases where the original is a lithograph, engraving or wood-cut, the best 

 effect will be produced by employing an analogous photographic process. 



Photolithography or photozincograj^hy is generally applicable to all 

 subjects in dot or line, which can be printed in the lithographic press, except 

 very fine delicate engravings or drawings ; but if a block is required for 

 printing with type it must be produced by one of the photo-typographic 

 processes. The photo- collotype processes are of more general application and 

 may be used for every kind of subject whether in line or half-tone. Their 

 use is, however, restricted to subjects within the limits of a single negative, 

 and they do not present the same facilities for carrying out alterations and 

 corrections as the lithographic and engraving methods do, and thus their 

 value for reproducing maps &c. on which corrections may be required is 

 very much diminished. The fact of the printing surface being composed of 

 an unstable organic substance like gelatine gives these processes an element 

 of uncertainty which is a great drawback to their extended use on the large 

 scale, especially in hot climates, and a really satisfactory and simple photo- 

 mechanical process capable of reproducing any kind of subject without limit 

 of size within ordinary dimensions is still a desideratum. The photo- 

 engraving methods are the most suitable for high-class work which is likely 

 to repay the cost of the skilled hand-labour required to finish and prepare 

 the plates for the press. A simple method of photo-engraving of general 

 applicability would be most valuable, and it is hoped that such a process 

 will before long be available. 



Use of Photography in War. — For the reduction and enlarging of 

 military and topographical sketches, and for multiplying copies of maps 

 and sketches required for use during a campaign, photograph}^ can render 

 great services. The principal supply of such maps should, of course, be 

 provided by a permanent office, established in a capital town and well 

 provided with the j^roper appliances. The extent to which photography 

 can be used in the field will depend on the character of the theatre of 

 operations, available water-supply and means of transport, as well as other 

 military considerations. In an open country with tolerably good roads, a 

 complete photographic equipment might be carried in wagons specially fitted 

 up for the purpose, and arrangements made for copying, enlarging or re- 

 ducing sketches, maps or plans, and printing them by photozincography or 



