In 1910 the conservation chemist Friedrich Rathgen cited an old
recipe, a concoction of 1.5 l vinegar, 12.5 g garlic, 25 g onions, 11.5 g salt,
80 g vermouth leaves, and 2.25 g ground pepper (Rathgen 1910:23–27;
Trillich 1924:23–27; Rasser 1925:42–43).
Beginning in the nineteenth century, oils from turpentine, juniper,
birch, clove, lemon, thyme, and lavender were recommended (Schiessl
1984:13). According to one source, boiling turpentine oil provides superior
penetration (Fernbach 1834:6). First mentioned in a conservation context
as “stone oil” (in Old German, Steinöl), petroleum and all its derivatives
have been used widely as conservation materials since the mid–nineteenth
century (Schiessl 1984:14). Similar to wax, petroleum derivatives imparted
the dark, heavy, metallic character of bronze color to the unpainted
wooden surface, especially to oak (Schiessl 1984:14). The same effects are
caused by tar oil. The newtaste for special surfaces and structures (the so-
called Materialgerechtigkeit) in the ear ly twentieth century is perfectly put
into words by Haupt, who stated that if the reverse of a panel painting
were impregnated with tar oil, the wood grain would be beautifully
intensified (Haupt 1908:559). The demand for noncoloring, nondarkening
conservation materials did not arise in the wood conservation field until
the 1950s. The trade names of “classic” mediums include Arbezol,
Basileum, Creolin, Carbolineum, Jakutin, Mobe R, and Xylamon (Brachert
1955b:27). At the time, all these materials consisted in part of mineral oils
that cause irre versible darkening of wood. Materials with the same trade
names are today formulated differently.
Industrial pest control products containing naphthalene chloride,
dichlorodiphenyltrichloride (DDT), pentachlorphenole, or lindane have
also been used, the latter in the former German Democratic Republic.
Most of these toxic agents continue to effloresce today from the treated
wood. Grav e concern about these highly toxic chemicals undoubtedly con-
tributed to the development of preventive conservation.H P P C A, G, S 211Figure 11
Master of Rottweil, God the Father with the
Body of Christ,ca. 1440. Reverse. Painting on
pinewood panel, 590 3 435 cm. Kunsthalle
Karlsruhe (inv. 1135; in the collection since
1858). The panel is one half of a double-sided
split panel; traces of the saw blade are visible.
All edges have been cut and reduced.