538 HANDBOOK OF PHOTOGRAPHY 



Uneven Emulsion. 



1. Distinguishing Characteristic. — Variations in thickness of emulsion. 



2. Cause. — Faultj^ manufacture and inadequate manufacturing inspection. 



3. Prevention. — None, except that such instances, which are fortunately rare, 

 are even more so with the products of reliable manufacturers. 



4. Remedy. — None. If the defective material is returned to the manufacturer 

 with a complete statement of all conditions, replacements may be made. 



Uneven Fixing. 



1. Distinguishing Characteristic. — Variations in density in areas of the negative 

 not related to the image produced on the negative. 



2. Cause. — Improper or incomplete immersion of the negative in the fixing bath. 

 The same result is obtained by allowing two or more negatives to come into contact for 

 prolonged periods in the fixing bath. 



3. Prevention. — -This defect may be prevented by separating the negatives in the 

 fixing bath, agitating the negatives and solution, and completely and entirely immers- 

 ing the negatives in the fixing bath. 



4. Remedy.— Isione. 



DEFECTS IN PRINTS 



This section deals with defects in prints made by contact or projection printing on 

 bromide or chloride papers. No consideration is given to defects due to coloring, 

 toning, retouching, or other af tertreatments ; other methods of producing prints, such 

 as printing with salts of other metals, bichromated colloids, the gum bichromate 

 process, oil processes, etc., are not considered here. For details on printing methods 

 other than those using silver halide salts, reference should be made to the appropriate 

 section of the book dealing with these other printing processes. 



Defects in negatives may show up as defects in prints. In this section it is 

 assumed that the negative is free from defects and hence that the defects actually 

 occurring are those due only to the printing process. 



Blotches, Lines, and Streaks 

 Abrasion Marks or Streaks. 



1. Distinguishing Characteristic. — Surface of paper abraded or scratched, often 

 resulting in fine scratches, especially when glossy-surfaced paper is used. 



2. Cause. — Scratching, abrading, or friction on the emulsion side of the paper. 



3. Prevention. — Store paper so that it stands vertically and is free from applied 

 pressure on its faces. Handle carefully. Make sure that processing solutions are 

 free from grit, undissolved matter, or foreign particles. 



4. Remedy. — Sometimes these abrasion marks may be removed bj^ adding ^g gr. 

 potassium iodide to each ounce of developing solution. 



Blurred Prints 

 Bad Definition in Spots. 



1. Distinguishing Characteristic. — Spots of print blurred, as if out of focus. 



2. Cause. — Imperfect contact between negative and paper in contact printing, 

 so that those portions of the negative which are slightly removed from the surface 

 of the print do not print sharply. 



3. Prevention. — Make sure that the printing device presses the printing paper into 

 firm contact with the negative during contact printing. Frequently the difficulty is 

 due to worn padding on the pressure top of the printer or loosening of the pressure 



