The Feast of the Gods is a three layer cake whose structure is revealed by slicing it. These slices, called cross-sections, give us snapshot views of the painting sequence. To take a cross-section, a half millimeter sliver is cut along a crack, mounted in plastic, and sectioned. Viewed under a microscope, we see the paint layers and identify their pigments.
Samples are usually taken near existing damage, like this paint loss in the meadow. In the example above, we see a bright green meadow, vivid green shrubbery, and dull brown tree trunks. Cross-sections complement other methods.
X-rays and infrared reveal superimposed layers; cross-sections reveal their sequence.