In a year or two (a lot less time if exposed to any heat) all your TITO slips will be turning brown and/or black so the only printing you will have left on them is the original ink printing on the back. Does anybody know of a way to stabilize or extend the shelf life of thermal paper?? In one of the hospitals I worked at medical records made photocopies of all the thermal print ECGs (ElectroCardioGram)when a patient was discharged. They had been pulling out old records to compare past heart tracings and found a lot of brown and black paper with no readable printing left on them.