brought changes in outlook and artistic expression as secular and landscape imagery overtook biblical scenes. Sacred imagery was shown in a didactic and moralistic manner, with religious figures becoming marginalized and relegated to the background. Pieter Bruegel the Elder, one of the few who followed Bosch's style, is an important bridge between the Early Netherlandish artists and their successors. His work retains many 15th-century conventions, but his perspective and subjects are distinctly modern. Sweeping landscapes came to the fore in paintings that were provisionally religious or mythological, and his genre scenes were complex, with overtones of religious skepticism and even hints of nationalism. Technique and material Campin, van Eyck and van der Weyden established naturalism as the dominant style in 15th-century northern European painting. These artists sought to show the world as it actually was, and to depict people in a way that made them look more human, with a greater complexity of emotions than had been previously seen. This first generation of Early Netherlandish artists were interested in the accurate reproduction of objects (according to Panofsky they painted "gold that looked like gold"), paying close attention to natural phenomena such as light, shadow and reflection. They moved beyond the flat perspective and outlined figuration of earlier painting in favour of three-dimensional pictorial spaces. The position of viewers and how they might relate to the scene became important for the first time; in the Arnolfini Portrait, van Eyck arranges the scene as if the viewer has just entered the room containing the two figures. Advancements in technique allowed far richer, more luminous and closely detailed representations of people, landscapes, interiors and objects. Although, the use of oil as a binding agent can be traced to the 12th century, innovations in its handling and manipulation define the era. Egg tempera was the dominant medium until the 1430s, and while it produces both bright and light colours, it dries quickly and is a difficult medium in which to achieve naturalistic textures or deep shadows. Oil allows smooth, translucent surfaces and can be applied in a range of thicknesses, from fine lines to thick broad strokes. It dries slowly and is easily manipulated while still wet. These characteristics allowed more time to add subtle detail and enable wet-on-wet techniques. Smooth transitions of colour are possible because portions of the intermediary layers of paint can be wiped or removed as the paint dries. Oil