Beurs’ historical recipe and material perception of grapes in Dutch Golden Age still-lifes

Intensive observation of the world, and the intention of realistically transferring it to the canvas, allowed Dutch Golden Age painters to develop an implicit knowledge of the visual patterns people use to infer different materials, imitating key optical phenomena via shortcuts. To understand the origin of the astonishing realism of Dutch 17th century paintings, we refer to the treatise of Willem Beurs, "The Big World Painted Small", a precious source of technical information about oil painting. One of the questions we aim to answer is: how did they produce such true-to-life depictions? We chose the representation of grapes as case study, due to the simultaneous presence and interaction of different material properties, like glossiness, translucency and bloom. Glossiness and translucency are of primary importance in vision science. Thus, understanding their rendering and perception for the case of grapes, can lay the groundwork for a more general theory of gloss and translucency. We investigated if the material properties proposed by Beurs to paint grapes are actually perceived in paintings, and how they relate to their perceived convincingness. Among these material qualities, we took a closer look at glossiness and tried to predict its perception via image statistics of specular reflections.