Thermochromic inks are a type of chromogenic printing inks that change their coloration under the influence of temperature changes. There are two types of thermochromic inks; inks based on leuco dyes and inks based on liquid crystals and they differ by the type of the active thermochromic material. This paper will examine the specific optical properties of the thermochromic printing inks based on liquid crystals in the visible part of the spectrum. These inks are the only printing inks that allow color changing within the entire visible spectrum in a certain temperature range. Currently, thermochromic printing inks based on liquid crystal are not in wide commercial use, but they are used for printing temperature indicators and similar applications. The reason for that could be the specific optical properties of those inks, which will be the subject of highest interest of this research. Spectrometric examinations will be performed on two types of inks based on liquid crystal with different activation temperatures in a wide temperature range, for each temperature shift. This type of examination will give an explanation of the specific optical effect of inks based on liquid crystal, which will be complemented with the CIELAB colorimetric analysis. This detailed examination of the optical properties will provide new information about the possibilities of wider application of thermochromic printing inks based on liquid crystals.