Beyond Black and White: The grisaille exterior of the Netherlandish triptych

This thesis is a study of fifteenth- to mid sixteenth-century Netherlandish triptych exteriors, focusing on the so-called ‘grisaille’ technique. During this period, altarpieces produced in the Low Countries were typically constructed in a tripartite format with folding wings. This arrangement created the opportunity for pictorial representations on both sides of the hinged panels. Painters emphasized the distinction between the triptych’s two faces by executing the exteriors in a strikingly more subdued palette than the interiors. Particular iconographic subject matter was favoured for grisailles, which often depict the Annunciation or saints that reflect the triptych’s patronage or intended location. Jan van Eyck was notable for his emphasis on imitating stone statuary and created three important grisailles, one of which would influence triptych exteriors for years to come. Hieronymus Bosch, an artist working at the turn of the sixteenth century, also brought innovation to his grisailles, further expanding the potential of these reduced-palette paintings. This thesis examines the creative process involved in the production of grisailles and compares the underdrawings of triptych exteriors to those of the corresponding polychromatic interiors. In this study, grisailles are situated in their context as part of multifaceted artworks as well as within the broader church environment. New infrared reflectograms were generated using Queen’s OSIRIS infrared camera to document works in Belgium and the Netherlands. While some aspects of underdrawings could indicate that the figure was meant to imitate statuary, this distinction was not directly linked to triptych exteriors and was related instead to efforts at a trompe-l’oeil effect. Such attempts at mimicry can also be found on triptych interiors. Through a close examination of the underdrawing stage of these paintings it appears that this part of the creative process was not distinguished in any significant way from the underdrawings of triptych interiors.

Refractometry Studies of the Optical Properties of Polymer Films and the Development of Polymer Coated Refractive Index Sensors

Sensors for real-time monitoring of environmental contaminants are essential for protecting ecosystems and human health. Refractive index sensing is a non-selective technique that can be used to measure almost any analyte. Miniaturized refractive index sensors, such as silicon-on-insulator (SOI) microring resonators are one possible platform, but require coatings selective to the analytes of interest. A homemade prism refractometer is reported and used to characterize the interactions between polymer films and liquid or vapour-phase analytes. A camera was used to capture both Fresnel reflection and total internal reflection within the prism. For thin-films (d = 10 μm - 100 μm), interference fringes were also observed. Fourier analysis of the interferogram allowed for simultaneous extraction of the average refractive index and film thickness with accuracies of ∆n = 1-7 ×10-4 and ∆d < 3-5%. The refractive indices of 29 common organic solvents as well as aqueous solutions of sodium chloride, sucrose, ethylene glycol, glycerol, and dimethylsulfoxide were measured at λ = 1550 nm. These measurements will be useful for future calibrations of near-infrared refractive index sensors. A mathematical model is presented, where the concentration of analyte adsorbed in a film can be calculated from the refractive index and thickness changes during uptake. This model can be used with Fickian diffusion models to measure the diffusion coefficients through the bulk film and at the film-substrate interface. The diffusion of water and other organic solvents into SU-8 epoxy was explored using refractometry and the diffusion coefficient of water into SU-8 is presented. Exposure of soft baked SU-8 films to acetone, acetonitrile and methanol resulted in rapid delamination. The diffusion of volatile organic compound (VOC) vapours into polydimethylsiloxane and polydimethyl-co-polydiphenylsiloxane polymers was also studied using refractometry. Diffusion and partition coefficients are reported for several analytes. As a model system, polydimethyl-co-diphenylsiloxane films were coated onto SOI microring resonators. After the development of data acquisition software, coated devices were exposed to VOCs and the refractive index response was assessed. More studies with other polymers are required to test the viability of this platform for environmental sensing applications.