The aim of this thesis is to examine the effectiveness of eco-fonts in reducing toner consumption and the perceived visual differences between regular fonts and eco-fonts by observers. The thesis consists of two parts - a theoretical section and an experimental section. The theoretical part involves a review of previous research related to the consumption and readability of eco-fonts. The experimental part is divided into two sections. The first part examines the effectiveness of three self-designed eco-fonts in reducing toner consumption. The second part examines the ability of observers to perceive differences between samples with regular fonts and eco-fonts. The research results have shown that significant savings are possible through the use of eco-fonts, and the visual differences between prints with regular fonts and eco-fonts should not drastically affect communication with readers at commonly used font sizes for text. From this, it can be concluded that further research is justified to determine the harmony - the size and shape of the empty space in eco-fonts that achieve a sufficiently large savings in ink consumption while minimally affecting the perception of observers. The advantage of such research is both ecological and economic in nature.