Abstract: To prepare a re-usable lithographic printing plate for printing, an imaging deposit is projected on the plate surface by jet printing using an ejectable substance containing a heat fusible component. The substance forms an imaging deposit which is fused to the surface of the printing plate (1) using a variable frequency and variable power induction heater (5). After printing the imaging, the deposit can be removed from the surface of the printing plate (1) using the same variable frequency induction heater (5) but transferring heat energy at a higher effective energy level to the fusible substance.

Abstract: A defect location signal such as has been used on television film scanners to show that presence of scratches or dust specks on the scanned film is utilized to show the horizontal extent as well as the position of a defect affecting successive pixels on a television line. Beginning at some point preceding the defects and ending at some time following the defect, the succession of undisturbed pixel values is time expanded with interpolation of pixel values to the extent necessary to bridge the entire defect region. The spacing between detected defects is measured to control the number of undisturbed pixels at each side of the defect that will be spread apart by interpolated values and likewise the ratio of interpolated values to undisturbed pixels in the expanded signal.