160 W, Crookes on the Wax-paper Photographic Process. 



2nd. To avoid all hurry and confusion, it is of the utmost im- 

 portance that the prepared paper or other medium, be of a kind 

 capable of retaining its sensitiveness for several days. 



3rd. The contraction which paper undergoes during the nu- 

 merous operations to which it is subject in most processes, (in 

 general rather an advantage than otherwise,) is here a serious 

 objection ; for this reason, the experiment first tried, of trans- 

 ferring to paper the., image received on collodion preserved sen- 

 sitive by the nitrate of magnesia process, was a failure. 



4th. Strong contrast of light and shade, and absence of half 

 tint, unfortunately so common amongst ordinary photographic 

 pictures, is in this case no objection. 



5th. It is essential to preserve the original results in an ac- 

 cessible form ; and for this reason, the daguerreotype process, 

 admirably as it seems to answer other requisites, is obviously 

 not the one best suited to our purpose. 



Lastly, the whole operation should if possible be so easily re- 

 ducible to practice, that with a very small share of manipulatory 

 skill, the loss of even a day's record would be impossible. 



2. Bearing these conditions in mind, on looking over the pho- 

 tographic processes with which I was acquainted, that known as 

 the wax-paper process, first described by M. Le-Gray, seemed 

 peculiarly applicable. In sharpness it might be made to rival 

 collodion ; and although generally stated to be slow in its action, 

 I had no doubt that its sensitiveness could be easily increased to 

 the required degree. 



Of all paper processes, I believed it to be one of the most free 

 from contraction, either during the time it is undergoing the 

 action of the light, or in any subsequent stage. Its chief supe- 

 riority, however, consisted in its capability of remaining sensi- 

 tive for so long a time, that it is of little consequence whether 

 the sensitive sheets be a day or a week old. Then the compara- 

 tive slowness of the development, which has always been looked 

 upon as one of its weak points, would be in this case a positive 

 advantage, as dispensing with that care and attention which 

 must always be bestowed on a quickly developing picture. 



In addition to all these recommendations, it was a process to 

 which I had paid particular attention, and consequently the one 

 in which I might naturally hope to meet with the greatest 

 amount of success. 



3. The general outline of the process does not differ materially 

 from that which I published some years back in "Notes and 

 Queries," vol. vi, p. 443 ; but as that account was written for 

 practical photographers, the details of the manipulations were 

 brief. It has therefore been thought advisable, that while de- 

 scribing again the whole process, with the addition of such mod- 

 ifications as the end in view requires, I should also give a fuller 



