Nikolai Ivanoviya Podklyuchnikov is an icon painter and restorer. Based on archival documents from the collection of the Ostankino estate museum

One of the most interesting representatives of the serf intelligentsia of the 19th century was Nikolai Ivanovich Podklyuchnikov, a serf of Count Sheremetev, who gained his freedom and established himself as an artist, restorer and collector. The article deals with documents from the collection of the Ostankino Estate Museum, which make it possible to assess N. I. Podklyuchnikov's contribution to the creation of scientific restoration of icons and paintings, the foundations of which, its main approaches, were laid by him in the middle of the 19th century. The method of layer-by-layer clearing of the monument in combination with preliminary samples to determine the preservation of the oldest colour layer is one of the main requirements of modern scientific restoration and is still used today. Special attention was paid by N. I. Podklyuchnikov to the ‘Passport of Restoration’, the scientific description of the object and its depiction at each stage of restoration. The article also offers to get acquainted with previously unpublished documents, including an unknown watercolour by N.I. Podklyuchnikov, preserved in the museum's archive.