Colorimetric properties of UV-thermochromic inks

The focus of this paper is on thermochromic inks that change colour in a controlled way when the temperature is varied. We will analyse here colorimetric properties of the screen-printed UV-curing leucodye thermochromic inks in red, blue and black shades with activation temperature of 31 °C. The inks will be screen printed on a gloss paper and on an aluminium board using one, two and three layers of colour. The samples were measured by spectrophotometer at three different temperatures: low, room and high. To see how the thickness of colour layers and UV-curing parameters influence the colorimetric properties, the reflectance spectra and temperature dependent CIELAB colour values will be shown. Also, the colour differences between the ink in different states together with colourless state and paper substrate will be calculated.