DEFECTS IN NEGATIVES AND PRINTS 527 



Irregularly Shaped Spots. 



1. Distinguishing Characteristic. — Spots of irregular shape; often along the edge 

 of the negative but rarely uniformlj' over the entire negative. 



2. Cause. — Exhausted developer. 



3. Prevention. — Use of fresh and properly compounded developer. 



4. Remedy. — None. 



Microscopic Spots. 



1. Distinguishing Characteristic. — Small, light, or transparent spots, irregular in 

 shape and small or microscopic in size. 



2. Cause. — Dust deposited on the negative. 



3. Prevention. — Keep negative free from dust, in the camera as well as in the dark- 

 room. Keep camera bellows clean by brushing dust out regularly. In the darkroom 

 keep negative protected until ready for processing. Dust may be removed from the 

 dry negative by playing a camel's-hair brush over the negative. 



4. Remedy. — Careful spotting or retouching. 



Mottled Appearance. 



1. Distinguishing Characteristic. — Mottled appearance of part or all of image. 



2. Cause. — Probably due to (o) lack of agitation during development, (b) absorp- 

 tion of moisture by the film before development, (c) use of old film, or (d) possibly 

 oil spots. 



3. Prevention. — (a) Keep developing solution agitated, (b) Store unused nega- 

 tives in cool dry atmosphere until ready for use. (c) Use films before date of expira- 

 tion of manufacturer's guarantee. 



4. Remedy. — None. 



Oil Spots. 



1. Distinguishing Characteristic. — (a) Chain of small gray areas. (6) Irregular 

 light-gray areas, (c) Mottled areas, {d) Black spots, (e) Black spots with white 

 centers. (/) Stippled streamline effects. 



2. Cause. — Oil on the surface of the negatives. The fine small areas are due to 

 thin spray of fine oil drops; the larger areas are due to oil spread over negative. 



3. Prevention. — Keeping oil from contact with negative. Ordinarily this is not 

 difficult, and oil spots are probably most frequent in machine processing of motion- 

 picture film. In this case, proper design and use of processing equipment will do 

 much to reduce to a minimum damage from oil spots. 



4. Remedy. — No remedy if processing is begun before detection of oil spots. If 

 oil marks are discovered prior to development or other processing, they may be 

 removed by (a) emulsification of the oil with sodium carbonate solution previous to 

 development or (b) dissolving the oil through the use of carbon tetrachloride or ben- 

 zene, after which the negative should be squeegeed and dried thoroughly before 

 developing. 



Opaque or Semiopaque Spots. 



1. Distinguishing Characteristic. — Small, irregularly shaped dark or black spots. 



2. Cawse.— Most commonly caused b.y undissolved particles in the developer, but 

 may be result of iron in solution in the wash water. 



3. Prevention. — All chemicals should be thoroughly dissolved before solutions are 

 used. When two sohitions are used, the constituents of each should be thoroughly 

 dissolved before the solutions are mixed. Filtering solutions is also helpful. 



4. Remedy. — None. 



