The diversity of colours is one of the most typical features of vernacular architecture. The submitted study deals with the research on the use of ultramarine on the Pannonian type of folk house, which could be found in central, southern, and south-eastern Moravia. The authors primarily proceed from the younger shift of the house. This featured, among other things, mainly the original transformation of stylistic elements, the façade segmentation, and the diversity of colours used on the frontages of residential buildings. Blue pigments were only barely available by the early nineteenth century, especially in the rural environment. The use of blue pigments flourished in vernacular architecture only after 1828, when the technique for the production of ultramarine was published. This was followed by industrial production of this pigment. The technique for the production of ultramarine, applied in the past, is described e. g. in the publication Tovární výroba barev [Factory Production of Dyes] by Jaroslav Milbauer from 1926. The treatise interconnects the cultural-historical and the technical level of the phenomenon under study. The material-analytical section is based on ethnological field research and an analysis of historical plasters using both physical-chemical methods of their identification and the knowledge of material engineering. Ethnological knowledge thus acquires a completely new dimension, and it is supplemented by new conclusions. At the same time, it is also a detailed analysis of the structure of ultramarine currently acquired on our market and an attempt at its laboratory synthesis. The result of the presented experiment with the production of blue pigment can be beneficial in practice for restoration purposes and professional analysis of historical plasters.