A major source in the research on Baltic cultural history (Latvia, Estonia), including studies dedicated to the clothing of local inhabitants, are the drawings and descriptions of Johann Christoph Brotze (1742–1823), which date back to the turn of the 18th and 19th centuries. They contain references to dyes and dyeing methods used by local peasants. The information recorded by J. C. Brotze, although fragmentary, is valuable because researchers lack documentary sources about the dyeing methods used in the 18th century in the territory of present-day Latvia. Additional research yields more extensive information about the contents of the descriptions. The current article will describe the experimental method that enabled the establishment of the specific dyeing technique, which, using Bixa orellana L., was employed to obtain the particular orange color referred to in the descriptions.