122 PRACTICAL PHOTO-MICROGRAPHY. 



This bath tones and fixes at one operation. To judge of the 

 color we must look through the print, reflected light will mis- 

 lead us. It is not easy to overtone by this process. 



Obernetter's Aristotype paper has in our hands worked best 

 with separate toning and fixing baths. 



TONING SOLUTION. 



Ammonic sulpho-cyanide T40 grains 



Sodic phosphate 140 grains 



Sodic tungstate. 100 grains 



Water 24 ounces 



Dissolve. Put in scraps of paper as above, filter, then add : 



Auric terchloride 15 grains 



Water 4 ounces 



Tone to a rich brown color or into blue if desired then, 

 after washing, fix in weak hypo ; viz. : 



Hypo 1 part 



Water 10 parts 



These papers may be dried with their natural surface or 

 may be highly glazed by squeegeeing to ferrotype, vulcanite, 

 talced glass, or collodionized talced glass, as described in last 

 chapter. 



