3 RESULTS

Our research has brought to light examples of the following blue pigments: indigo, azurite, smalt, and Prussian blue. We found them employed in three ways:

1. singly and exclusively in a painting or a homogeneous series of works
2. combined in different layers of blue in the same painting
3. mixed on the palette and applied as a mixture in a single layer of paint

In each category, we grouped the pieces according to their origin (either certified or attributed with a high degree of probability). We identified the artists, either documented or proposed as a result of indicative attribution techniques (overall style, details of execution in the faces, hair, hands and clothing, etc.), and the dates of execution, both documented and probable. Within each subgroup of origin, the order of presentation is chronological beginning with the oldest work. (See appendix.)