Section 4 | Page 8

The density range between the highlight and the shadow areas can vary from one image to another. One image may have a narrow tonal range while another image can show a wide tonal range. Regardless of the tonal range, the number of density levels in a continuous-tone image far exceeds the number of density levels in a screened image. In other words, the number of density levels of an original is usually far greater than what is achievable on press.

This means the tonal range of an original image

must be compressed during the image reproduction process. The result is tone compression which requires that certain parts of the tonal range must be emphasized at the expense of others. Because of this inevitable compromise, a decision must be made as to what parts of an original image are the most important to reproduce accurately. The entire tonal range of an original is usually difficult to reproduce on press. Detail in the highlight areas may have to be sacrificed to hold the detail in the shadow areas, or vice versa.