SAFELIGHTS 



237 



velopment is made easier. A similar device may be used 

 for red lights, and is particularly useful when two or more 

 shutters cover a window ; one may be drawn aside and 

 the light from the narrow section of the others used as 

 above. 



Testing Safelights. The safety of the lamp screen can 

 be examined by developing a plate, half of which has been 

 exposed for ten minutes to the usual developing light, 

 while the other half was kept covered. The development 

 should be carried out in a covered dish for the normal 

 time required by the developer used, and any darkening 

 of the exposed half as compared with the other will 

 indicate that the light must be attended to. 



