Samuel van Hoogstraten, Old Man at the Window, 1653, Kunsthistorisches Museum, Vienna.

Samuel van Hoogstraten’s painting Old Man at the Window (1653, Kunsthistorisches Museum Wien) recapitulates the impact of the Eyckian turn in Netherlandish painting, which laid the foundations for the detailed and realistic depiction of the visual world. This achievement became iconic through the rendering of single hairs in beards and fur, of life-like human skin or painter’s signatures scratched in weathered and chipped stone frames. While Hoogstraten’s references have been acknowledged in recent art historical research, there is yet another element that alludes to the origin of the illusionistic tradition: the little glass bottle on the windowsill. Not only does it contain the medium that made possible the painterly revolution—its particular position also demonstrates a crucial preparatory process: the thickening and bleaching of linseed oil through continuous exposure to sunlight, made possible by another see through substance, glass. It was through this process that the use of oil as binding medium could be extended to include white, ochre, and yellow pigments, allowing for all picture elements to be painted in the same medium, probably the most crucial factor to incite the Eyckian turn.

The representation of this process is common in painter’s self-portraits and studio scenes in seventeenth-century Netherlandish paintings and can be traced back across the iconography of St. Luke painting, all the way to the Ghent Altarpiece, where a similar bottle on a windowsill is depicted for the first time. The bottles containing yellowish fluid are placed on windowsills or hung near windows from a thread to be exposed to sunlight; a treatment also described in contemporary recipe literature. In Van Hoogstratens painting, the tiny bottle and the inconspicuous substance it contains, sometimes described as witte olie, presents the material interaction between oil, glass, and light that enabled oil painting on a technical level. At the same time it showcases the illusionist power of that technique at the level of representation: the intricate patterns of shadows and reflection produced by the particular material interplay at hand.

This project took the oil-filled bottle as a starting point to research

  1. the material prerequisites for preparing linseed and other oils for painting in the Southern Netherlands around 1400
  2. the transmission of knowledge about the material properties of oil and its appliances through visual sources in relation to textual transmission in recipe literature and art theoretical writings

The first part drew on archeological research about the manufacturing of small glass vessels in Flanders and Germany during the fifteenth century as an important and hitherto unstudied source for the history of oil as a painting medium. It aimed to understand how the emerging industry of simple, household glass benefitted the structural preparation of oil for painting purposes, arguing that the availability of such vessels may have been pertinent to the study and ensuing discovery of oils’ particular properties to thicken and bleach if continuously exposed to light, while keeping out dust. Next to the history of glass production also the history of linseed oil as a co-product of the flax industry in Flanders is studied to imbed the particular history of oil as painting medium in the wider context of its manufacturing and diverse applications.

The second part traced the iconography of the glass bottle filled with transparent substances as it appears from the 1430s onwards in scenes pertaining to artistic and craft practice—including studio scenes, title pages of art theoretical treatises as well as depictions of craft processes, e.g., Jos Amman’s Ständebuch. The bottles are related but also distinguishing from contemporary depictions of alembics that explicitly reference alchemical practices: both can be understood to signify material containment and transformation. The depiction of bottled oil is further compared to recipes and art theoretical texts about the preparation of oil for panel painting, which, as far as known sources suggest, emerge later than these visuals. This leads to the more theoretical question of how images exactly functioned in the transmission of implicit, material knowledge about their own production and if the pictorial affordance to condense complex material processes helped to make such processes explicit prior to written sources. These, it is contended, are typically concise and seem to convey only a small part of the actual processes involved in preparing oil and painting with it. In other words, can the bottle and its persistent iconography be understood as visually archiving and actively transmitting the material knowledge of painterly practice?