82 



degrees of actinity. Thus green and red acts very 

 slow, whereas blue acts quickh\ Isochromatic plates 

 and ray filters correct these effects. 



As to the development of the exposed plate the 

 ordinar}^ processes for bringing out detail are used. 

 Dark and under-exposed parts of a negative may be 

 urged along by taking the plate out of the bath at 

 intervals and breathing upon the parts in question. 



Finally to make the prints, the platuium papers 

 have proved most satisfactorih% giving both definition 

 and artistic effects. Then also the different tones of 

 brown, yellow, black and olive possible to attain with 

 these papers, when appropiateh' applied do much to 

 enhance the beauty of the pictures. 



Since time and space will only permit of referring 

 to a few of the chief points to be observed, this paper 

 must be limited to the afore -said. 



Although it can hardly be assumed that plant 

 photography would be practical for illustrating 

 elementary botanies, it is beside being a fascinating 

 study in itself an interesting and attractive way of 

 recording manv botanical observations. 



