136 SCIENCE OF HOME AND COMMUNITY 



held from the light. For holding the negative and paper, a 

 printing frame is used. The paper should be handled in a 

 room with subdued light and brought near the source of 

 light only at the time of exposure. After exposure the paper 

 is placed in a developing solution till the printing has reached 

 the desired stage, then it is dipped in water and placed in 

 hypo, as was done with the negative. The paper is then 

 placed in running water for a few minutes or in five or six 

 changes of water, and is then taken out and dried. 



Blue prints. The blue print is an example of a printing 

 out paper. It is one of the easiest papers to use because it 

 does not require any special chemicals, water being the only 

 thing needed. The chemicals on this paper are compounds 

 of iron instead of silver. This paper requires a long time to 

 print. The picture shows during the process of exposure, 

 and the process may be watched by opening one half of the 

 back of the printing frame. 



Mounting. The prints may be mounted by using a dry 

 mounting tissue, which comes in thin sheets and may be 

 applied by pressing with a hot flatiron. Or the prints may 

 be soaked in water and then mounted by using starch paste. 



DEMONSTRATION 18 



Purpose. To show how to print pictures. 



Apparatus. Developed films, printing frame, blue-print 

 paper, some developing paper like velox and the necessary 

 chemicals for using it. 



Directions, i. Make a print with blue-print paper, follow- 

 ing the directions that come with the paper. 



2. Also make a print from the same negative, using a develop- 

 ing paper and following the directions that come with it. Use 

 one of the slow printing papers. This may be done, during the 

 daytime in the schoolroom, if the curtains are pulled down and 

 if the paper is put into the frame in a drawer or closet that is 

 partly darkened. 



