The article deals with the spelling of proper nouns on popular engravings (lubok, pl. lubki) and on icons of the 17th–19th centuries. In the 17th century, as a result of the editing of church books, the spelling of proper nouns was normalized in accordance with the Greek orthography. Proper nouns are also subject to these rules in modern liturgical books. One could assume that proper nouns would be spelled in the exact same way on icons (engraved and painted) where such nouns accompany the images of saints. However, this is not true. The spelling of proper nouns obeys book rules neither on popular engravings, nor on icons. Thus, letters of Greek origin (such as ѯ, ѱ, ѵ) may be changed to кс /ks/, пс /ps/, и /i/ or в /v/. The letters ф and ѳ are used interchangeably, their spelling does not depend on etymology, as is also the case with ҍ and е, which are Slavic in origin. Such spelling features are also characteristic of both inscriptions on icons and captions to engraved images of saints. Therefore, in lubok tradition and on icons, proper nouns are not in compliance with the Church Slavonic orthographic norm. Such spelling can be correlated with the handwritten practice of the 17th century, which was partly preserved in subsequent times. The orthography remained quite liberal in handwritten texts of the 18th century and even in those of the first half of the 19th century. In this regard, icons and lubki are similar to letters and personal documents of the 18th century. The spelling rules used in the printing of liturgical books were only used by professional proofreaders and editors.