Abstract: A high ratio multilaced raster scan system for obscuring the blank spaces between the raster lines on a CRT when making a photograph or hard copy from the screen of the CRT utilizes a selectively varied DC bias voltage to vertically offset in a select sequence succeeding pulses in the vertical ramp pulse train signal which controls the vertical sweep position of the electron beam of the CRT to thereby provide a corresponding sequence of parallel interlaced raster lines vertically offset with respect to each other. The system is calibrated in a simple manner by utilizing an alternating DC bias voltage to vertically offset alternate pulses in the vertical ramp pulse train signal and thereby enable the user to calibrate the average DC level of the selectively varied DC bias voltage by aligning the raster lines of the first and second fields.