TIME DEVELOPMENT 223 



temperature of the solution constant. The simplest way, 

 when the dark room is not too hot or cold, is to allow the 

 developer and dishes to stand until they attain its 

 temperature. Errors in the time of development, follow- 

 ing correct exposure, are evidenced by a too great or too 

 small degree of contrast in the resulting negative, and 

 the time should be reduced or increased for future 

 negatives. 



Stand or Tank Development is a modification of time 

 development, whereby half a dozen or a dozen plates 

 are developed at once in a dilute solution of developer. 

 The ordinary dish development is more economical when 

 only a few plates are to be developed, but a tank is 

 invaluable when many plates can be developed at once, 

 saving time and rendering needless a long stay in the 

 dark room. The plates are placed in a grooved holder in 

 a covered box, and sufficient developer is poured in to 

 cover them well, care being taken by judicious movement 

 of the plates or of the box as a whole, at frequent intervals, 

 to prevent air bubbles , and to keep the developer suffi- 

 ciently shaken up. The solution is used very much more 

 dilute than in a dish, and development is correspondingly 

 prolonged, say from 15 to 30 minutes, according to 

 developer and temperature. The only part of the process 

 that need be carried on in the dark-room is that of filling 

 the tank with plates and pouring on the developer. With 

 many of the tanks on the market the latter operation, and 

 also washing and fixing, may be done in daylight, a light- 

 tight funnel being fitted to allow admission of solutions. 

 But the slow pouring in of developer often leads to lines 

 across the negative due to momentary high-water marks 

 as the solution creeps up. Times for stand development are 

 given with the suitable developers on page 269. Particu- 

 lar attention must be paid to keeping the temperature 

 constant if time is to be relied on alone, and it is advisable to 

 examine each plate before placing it in the fixing bath to en- 



