In this thesis, the study was conducted to determine colorimetric characteristics of thermochromatic screen printing on different printing surfaces. The color which was used is based on leuco dyes. By its properties, such colors are reversible, which means that during the heating process their coloration changes, and by cooling down the color goes back into the original state. For this experimental study, thermochromatic leuco dye was printed on five different printing surfaces (papers). For examination of printed samples and determination of their colorimetric characteristics, the spectrophotometer Ocean Optics USB 2000+ and computer software SpectraSuite were used. To determine optical characteristics of thermochromatic colors, samples were first heated, and afterwards cooled in the device which is specially design for this purpose. This device is called EK Water Block, EKWB d.o.o, Slovenija. After all measurements were done, given results were processed and interpreted in charts. Chart which best describes characteristics of thermochromatic colors is called hysteresis. Thermochromatic system has a memory, or in other words, it is not possible to predict the output without knowing the way with which it came before currently accomplished state. Such a phenomenon is called hysteresis. Thermochromatic materials belong to a dozen of physical systems with hysteresis. This examination showed that change in coloring does not apply for activation temperature (TA), as defined by manufacturer, but rather on the temperatures near TA. Also, it was concluded that the color does not act the same on different printing surfaces and that smooth papers with a bigger amount of moisture and ash (filler) have a better effect on thermochromatic change during the heating process, and a lower effect during cooling.