PRINTING PROCESSES 



413 



desired print may depart widely from being an accurate representation of the original, 

 not only in tone value, but in the component parts which make up the scene. In the 

 hands of an artist, a print may have very little in common with the original scene, 

 since the artist has means of removing from the print any objectionable portion of 

 the original, or lacking a desirable element in the original, the artist may add this 

 element to the print. The tone values are frequently distorted for artistic purposes. 



Color photography, however, is as yet a realistic medium, in which the effort is 

 made to make an accurate representation of the original. In time it is probable that 

 photographers will learn how to make use of certain distortions in color photography 

 as they have in monochrome — all with the aim of producing a work of art rather than 

 an accurate representation of the original subject. 



The Printing Problem. — If the aim is to produce an accurate reproduction of the 

 original scene, the photographer must consider the following factors, which are con- 

 sidered in greater detail in the chapter on Photographic Sensitometry. 











4 



1 2 3 



Brightness Units 



Fig. 1. — Effect of negative development on compressing or increasing opacity range with 

 respect to scene brightness range. 



The original subject reflects light in varying degrees depending upon the nature 

 of the illumination, and upon the color and reflectance of the component parts. It is 

 desired to have the final print show these differences in reflecting ability. It is possible 

 in processing the negative to compress the scale or brightness range of the original, to 

 expand it, or to make the negative show accurately the brightness differences of the 

 original. Thus, if the ratio between the maximum and minimum brightness of the 

 original is 20: 1, the opacity of the negative representing these portions of the original 

 may show a ratio of less than, equal to, or greater than 20: 1. 



If the scale is compressed, i.e., if this brightness ratio is reduced, the negative is 

 flat, whereas, if the opacity range is expanded, the negative is contrasty compared to 

 the original. If it is desired to make the print an accurate reproduction of the tone 

 values of the original, some compensation must be made for the fact that a flat or 

 contrasty negative does not accurately portray the original. 



Practically, the photographer performs these compensations by using a paper 

 which has less or more contrast. With the flat negative, in which the brightness range 

 of the original has been compressed, a contrasty paper should be used; conversely, a 

 "'soft" paper, lacking in contrast, should be used with the contrasty negative, the 

 degree of softness or contrast depending upon the degree of compensation required. 



