ELEMENTARY PHOTO-MICROGRAPHY. 53 



assist quick drying. If tap water be used for wash- 

 ing, it should be seen to that it is not charged with 

 air, which causes the gelatine to separate from the 

 glass. 



Running water, where available, is more effective 

 in dissolving out the hypo, from which the negative 

 should be freed. 



Sometimes a plate may have to be developed 

 late at night, when it would be risky to leave it 

 soaking in water till next day, especially in warm 

 weather. The Hypax tabloid in such a case will 

 be found an excellent substitute for prolonged wash- 

 ing. After the plate has been well rinsed it is put 

 in a dish and covered with water. Half a tabloid 

 of Hypax is put in one corner until all has been dis- 

 solved, the negative is then rinsed in clean water, 

 and the hypo will have been eliminated. 



A good fixing bath is made of four ounces hypo 

 dissolved in a pint of water. Vertical fixing in a 

 trough capable of fixing six negatives at a time is 

 recommended. After many plates have been fixed 

 a dirty deposit will be found at the bottom of the 

 trough. The liquid should be examined in full 

 fight after all the holders are removed, and if it is 

 muddy at the bottom it should be thrown away and 

 fresh made. With this precaution the holders and 

 fixing solution may be left in the vessel after use, so 

 that they are always ready. 



Negatives improperly exposed or developed may 

 appear quite black and opaque when examined only 



