Semi-irreversible temperature exposure sensor customizable by thermal printer

A method of creating an ascending temperature indicator, the method comprising:

• receiving a media having a direct thermal print region that darkens when it is heated by at direct thermal printer thermal printhead, the darkening being permanent with respect to subsequent cooling of the media, the media also having an indicator region with a memory thermochromic composition provided on the media, the thermochromic composition configured to have a low temperature color state when it is cooled below a low temperature threshold, and to remain in the low temperature color state until it is heated above a high temperature threshold, and a high temperature color state when it is heated above a high temperature threshold and to maintain the low temperature color state until it is cooled below the low temperature threshold, wherein the media is provided with the thermochromic composition in the high temperature color state,
• printing indicia on the media with a direct thermal printer in the print region;
• and
• placing a portion of the indicator region into the low temperature color state using a cooling agent to form a human readable indicia in the indicator region.