Early Work In Photography
A Text-book For Beginners

The After Treatment of Negatives. 93 possible to make a quick printer of a negative that was previously as dense as a brick wall. The action that takes place in the reducing bath is simply this: The potassium ferricyanide becomes converted into potassiumferrocyanid, and the metallic silver of the image (practically unaffected by hypo) becomes simultaneously converted into silver ferrocyanide, which is soluble in hypo. The hypo attacks the silver ferrocyanide and converts it into sodium ferro- cyanide and silver sodium thiosulphate. In other words: as fast as the insoluble silver is converted into a soluble salt it is dissolved in the hypo and removed, thus effecting reduction Irreduction takes place too slowly, use more red prussi- ate; more strictly scientific method of reduction, and the only one that is practicable with negatives possessing great for io or 15 minutes and covered (in daylight or th arken, chloride (visible on the glass side) is dissolved, it The advantage of this plan (especially with negatives ot - solved inthe hertatives, the result of over exposure and care- Plat toggy negative ialltle remedied by intensification; less development, can usually te to first reduce them slightly but in most cases it sac bath in order to remove the in the ferricyanide are extreme shadows. If this is not foggy deposit from tn gives the desired contrast, owing to the tact that the TOEHY deposit becomes intensified in the same proportion as the image.