To be clear, film protection bags don't work for scanners at all. And if the operator sees a blob he can't image, he is likely to back up the belt and increase

To be clear, film protection bags don't work for scanners at all. And if the operator sees a blob he can't image, he is likely to back up the belt and increase the power until he can. Film protection bags are to protect against fogging from radiation at higher altitudes, not the scanners.