Magnetic tape analysis 'sees' tampering in detail

This image, produced by the new NIST forensic tape analysis system, clearly reveals an overdubbing. The new recording is visible from the left bottom of the image to about 188 millimeters on the distance counter, the large smudge at 216 mm was made by the erase head, and the original recording is visible starting at about 220 mm. Credit: Credit: NIST