Method and apparatus for previewing exposed photographic films or the like

A method of examining a series of successive originals of varying sharpness, especially exposed and developed film frames, to allow for detection of those originals which are unfit for the making of reproductions, comprising the steps of moving successive originals to a predetermined position;

• photoelectrically scanning at least a selected portion of the original in said position and generating signals which are indicative of the characteristics of such selected portion;
• processing said signals to ascertain first maximum density gradients derived from the entire spectrum of said selected portion;
• processing said signals to ascertain second maximum density gradients derived from the lower-frequency portion of the spectrum of said selected portion;
• forming a quotient of the first and the corresponding second density gradients;
• and classifying the corresponding original as being suitable for reproduction when the quotient exceeds a predetermined threshold value.

A method of examining a series of successive originals of varying sharpness, especially exposed and developed film frames, to allow for detection of those originals which are unfit for the making of reproductions, comprising the steps of moving successive originals to a predetermined position;

• photoelectrically scanning at least a selected portion of the original in said position and generating signals which are indicative of the characteristics of such selected portion;
• processing said signals to ascertain the frequency and magnitude of first maximum density gradients derived from the entire spectrum of said selected portion;
• processing said signals to ascertain the magnitude and frequency of second maximum density gradients derived from the lower-frequency portion of the spectrum of said selected portion;
• determining the total number of those first density gradients whose magnitude exceeds a first predetermined threshold value;
• determining the total number of those second density gradients whose magnitude exceeds a second predetermined threshold value;
• forming a quotient of the total numbers of said first and second density gradients;
• and classifying the respective original as being suitable for reproduction when the quotient exceeds a predetermined threshold value.

Apparatus for examining a series of successive originals of varying sharpness, such as exposed and developed film frames, to allow for detection of those originals which are unfit for the making of reproductions, comprising means for moving successive originals of a series of originals to a predetermined position;

• means for photoelectrically scanning at least a selected portion of the original in said position, including means for generating signals which are indicative of the characteristics of such selected portion of the original in said position;
• means for utilizing said signals to ascertain the density range of the selected portion of the original in said position;
• means for processing said signals to determine the density gradient of at least one scanned region of the selected portion of the original in said position;
• means for forming a quotient of the determined density gradient and the density range of the respective selected portion;
• a source of reference signals denoting a predetermined threshold value;
• and means for comparing said quotient with said threshold value, an original being considered fit for the making of reproductions when said quotient exceeds said threshold value.

Apparatus for examining a series of successive originals of varying sharpness, especially exposed and developed film frames, to allow for detection of those originals which are unfit for the making of reproductions, comprising means for moving successive originals of a series of originals to a predetermined position;

• means for photoelectrically scanning at least a selected portion of the original in said position, including means for generating signals which are indicative of the characteristics of such selected portion of the original in said position;
• first processing means for processing said signals to ascertain first maximum density gradients derived from the entire spectrum of the selected portion of the original in said position;
• second processing means for processing said signals to ascertain second maximum density gradients derived from the lower-frequency portion of the spectrum of the selected portion of the original in said position;
• and means for determining the fitness of the original in said position for reproduction, including means for comparing signals denoting said first and second maximum density gradients.