Paintings are always examined first with the naked eye and under normal light. This direct study of the painting forms the basis for the entire investigation, the standard to which all subsequent research findings are compared. With a magnifying glass or microscope, a researcher can magnify details and features such as brushstrokes, cracks and fingerprints in the paint layer.
The next step in examining a painting is to look at it under raking light. A light source is placed to one side of the painting, so that the light ‘rakes’ across the paint surface. This method can be helpful when studying the paint texture.
It is also possible to place a light source behind the painting, so that it shines through the canvas, revealing any breaks, cracks, loss of paint particles or thin areas.
When exposed to ultraviolet light, the chemical elements of pigments, binders and varnishes glow fluorescent colours. Each colour indicates the presence of a specific element. This makes it possible to identify a range of pigments and varnishes. Ultraviolet light can also make later restorations clearly visible, because they fluoresce very differently from the original paint layer.