THE WOMBAT. 5:9 



URANOTYPE AND ITS CAPABILITIES.* 



At a recent meeting of the South London Photographic 

 Society Mr. Albert Hill treated the members to an interesting 

 demonstration of the working of a new printing process. The 

 process consists in the use of a paper sensitised with uranium 

 salts, and the name of " Uranotype " has been adopted as a 

 distinctive title. It possesses some remarkable qualities as to 

 capacity for giving distinctive colours according to treatment, 

 and promises to place a new power in the hands of the photo- 

 grapher. 



In the course of the demonstration Mr. Hill showed several 

 prints as taken from the printing frame, the image being 

 faintly visible, and somewhat similar to that obtained upon 

 platinotype paper at the same stage ; he then proceeded to 

 develope the picture, which is done either by immersion in a 

 bath, or brushing over with a solution of ferricyanide of potash ; 

 the latter was the method chosen by the demonstrator, and 

 immediately the solution was applied the image appeared in 

 full strength, the colour being somewhat of a Bartolozzi red. 

 If desired, the prints can at this stage be fixed by placing them 

 in a solution of sulphate of iron i part, water 6 parts, or if 

 slow action is wanted the sulphate may be less. In this bath 

 the prints go rapidly through various stages of red-brown, &c, 

 until they reach a deep blue and, if the action is allowed to 

 continue, a bright green. The action may be stopped at any 

 moment, so that almost any colour within certain limits may 

 be secured. A purple photographic tone may be obtained by 

 the use of a strong gold solution — gold 4 grains, water 1 oz — 

 and, as this strength is somewhat expensive, it may be 

 economically applied by means of the brush. The develop- 

 ment of the paper and its change of colour can be kept well 

 under control by using weak solutions, and a valuable feature 

 is that it is practically impossible to overprint, as, no matter 

 how long the picture may have been exposed to light or how 

 dark it becomes, on development it may be brought back to 

 its normal condition by immersion in a weak solution of 

 ammonia and water. Mr. Hill laid stress upon the fact that 

 all dishes used in the process must be kept perfectly clean, and 

 pointed out the great advantage that accrued from the entire 

 dispensing with hypo, in the process, thus enabling a print to 

 be developed, fixed, and dried (if required) in about ten 

 minutes. The drying may be done by heat, as there is no 

 gelatine coating on the paper. Mr. Hill also pointed out the 

 ease with which several colours could be produced on one 

 print by means of applying the various solutions with a baush, 

 thus the sky in a landscape may be made blue by the application 



*The British and Colonial Printer and Stationer. 



