LOW-POWER WORK 



33 



known as Thomas's Hydrokinone formula, we have always used with the greatest 

 satisfaction for the class of work under consideration : 



Solution I. 



Hydroquinone 

 Potassium bromide 

 Citric acid 

 Water . 



Sodium hydroxide 

 Water 



Potassium bromide 



Solution II. 



Solution III. 



x6o grains or 8 Gm. 

 40 ., 2 Gm. 



60 „ „ 3 Gm. 

 to 20 ozs. 440 C.c. 



160 grains or 8 Gm. 

 to 20 ozs. 440 C.c. 



I in 3 of water. 



It is our practice to always take two negatives of any object, each having a little 

 different exposure, and to develop both in a half-plate dish at one time. For this 

 purpose 6 fluid drachms of Solutions I. and II., and 6 drops of Solution III. are 

 taken, filling up to 16 fluid drachms with water. 



The prudent photographer will always periodically test his dark room to see if the 

 fabrics (or stained glass if he prefer it) still maintain their proper qualities. This is 

 done in a simple way as follows : 



A plate is put into the dark slide in total darkness, and the gaslight then turned 

 on. (It is a convenience to have the means of doing this from the inside of the room.) 

 The shutter of the slide is now partially drawn and the plate exposed about |- inch 

 for, say, 10 seconds; another ^ inch opened, the plate is further exposed another 

 10 seconds ; a little further and another 10 seconds until at length the whole plate is 

 exposed all hut a small portion, which should be kept intact as a check against the 

 appearances presented by the other portions after development. This process should 

 be of course carried on for a given time in absolute darkness and the plate washed 

 and placed in the "hypo" without turning up the light. The plate is afterwards 

 examined and should show no difference in any part. If it does the difference of time 

 required to produce the fogging shows the severity of the "leak." 



To -develop the two plates of which we have spoken, the developing solution is 

 thrown over them in one sweep so as to leave no irregularities on the plate ; which 

 inevitably occurs if by any chance one portion of the emulsion is covered with solution 

 a longer time than the rest. The dish should be violently agitated from side to side 



