What is the fine-grained topic of the following text: Thermal printing (or direct thermal printing) is a digital printing process which produces a printed image by selectively heating coated thermochromic paper, or thermal paper as it is commonly known, when the paper passes over the thermal print head.... 2/01/2017 · Use an iron to darken thermal receipts TWO TECHNIQUES FOR AGING PAPER with Coffee. Only return the topic.
Thermal printing and techniques for aging paper with heat and coffee.