Photomicrography 45 



(softest) to No. 5 (harshest). Figures 48 to 50 show the result of print- 

 ing a good negative on paper Nos. 1, 3, and 5. 



Surface. The only surface that can be considered for scientific prints 

 is glossy. All other surfaces, made for pictorial effects, reduce resolution. 

 The three best-known papers of this type are Eastman's Kodabromide F, 

 Dupont's R, and Ansco's Jet GL. The first is made in five, and the last 

 two in four, contrasts. 



PROCESSING PHOTOGRAPHIC MATERIALS 



Everything so far written has concerned the materials in which a latent 

 image is produced. This latent image is "processed" into an actual image. 



The Darkroom. It is difficult to process negatives and impossible to 

 process prints without an adequately equipped darkroom. 



The room itself must be so constructed that it is capable of being 

 made absolutely dark. Even the keyhole must be blocked and the base 

 of the door fitted with a pad to prevent light seepage. On the other hand, 

 the room must be light and well ventilated when not in use. Dark damp 

 cubbyholes are no use as darkrooms because they encourage dirt and 

 fungus, both equally ruinous to photographic equipment. The ceiling 

 should be white, to reflect the light of the safelights used when processing 

 papers. The walls should be medium to light green as a compromise be- 

 tween the cheerfulness of white and the risk of reflecting light escaping 

 laterally from an enlarger. Concrete floors and unpainted wooden shelves 

 are abominations that liberate dust and dirt to wreak havoc on the wet 

 and sticky surfaces of newly processed material. A large household re- 

 frigerator should house films, papers, and reagents. Steel cabinets provide 

 storage for everything else. An experienced photographer's darkroom, in 

 fact, is a very different place from the dingy cell that architects of science 

 buildings love to stick in an unwanted corner. 



The basic furniture of a darkroom is a flat-bottomed stone or stainless- 

 steel sink not more than 8 in. deep nor less than 4 ft long by 2 ft wide. 

 Along the opposite wall, as far from the sink as possible, should be a 

 sturdy bench. It is better to have two darkrooms: one "wet" for processing; 

 the other "dry" for enlarging, loading dark slides, and the like. 



There is no limit to the equipment that may be purchased for a dark- 

 room. Minimum equipment includes safelights, developing dishes, de- 

 veloping tanks, and an enlarger. The nearest photographic dealer should 

 be consulted, and his advice taken, by the inexperienced. Always buy 

 the best possible enlarger, and particularly enlarging lens, that you can 

 afford. There is no use going to great expense and trouble to produce a 

 crisp, well-resolved negative and then to project an image of this negative 

 through a second-class lens. The enlarger should have a good condenser 



