322 



OUR PHYSICAL WORLD 



the two sides is not as marked as in the plate. Put the back in 

 the print frame, and fasten it in by the spring clips so it w$l hold 

 the print paper firmly against the negative. Expose to the light 

 of the electric lamp so that it will fall on the face of the negative 

 and through it on the paper. The paper is then removed, devel- 

 oped, and fixed in the same way as a plate would be handled, 

 except that it is not necessary to wipe its face. The print should 

 be developed until it is a trifle darker than really desired as it pales 



a little in the fixing bath. 

 Slide the paper into the de- 

 veloper rapidly and see that it 

 is covered by the developer 

 at once. One uses a different 

 developer for prints than for 

 plates usually, one that gives 

 less contrasty results. Elon- 

 quinol, purchased in tubes, is 

 a good one to begin with. 

 One tube makes up 8 ounces 

 of developer, enough for a 

 dozen 5X7 prints. 



Just how long an exposure 

 is to be given to make a good 



print depends on the brand of 

 FIG. 163. Handling the film 



paper, the thickness or density 



of the negative, and the intensity of the light used. The print 

 frame may be held a foot or so from a fifty-candle-power -electric 

 light with a frosted globe. Cut a sheet of point paper into 

 several strips, and try one strip with an exposure of five seconds. 

 If the picture comes up in the developer clearly in ten seconds 

 or so, that exposure is about correct. If it flashes up suddenly 

 and the strip darkens all over, the exposure is too long. If it 

 comes up slowly and weakly, the exposure is too short. Try 

 other strips until the exposure is correctly timed, then print 

 the picture on the full-sized sheet. After some experience one 



