Image and pattern analysis for the determination of the method of drawing celebrated thera wall-paintings circa 1650 B.C.

In this article, an integrated conjecture about the method of drawing of monumental prehistoric wall-paintings is presented and supported. Specifically, the article deals with paintings that initially decorated the internal walls of the highest floor of a building, called “Xeste 3”, at Akrotiri of the Greek island of Thera circa. 1650 B.C. It is argued that these wall-paintings could had been drawn while the brush was guided by an apparatus, which corresponds to advanced for the era of geometric prototypes with impressive precision. A set of assumptions concerning the actions the artists might have taken in order to create the spiral themes is stated and supported. These assumptions refer to the existence of a draft plan, the sequence of brush strokes, the placement of the brush on the wall, as well as the possible form of the apparatus. These conjectures are evaluated and tested by means of curve fitting and image analysis methods developed by the authors. The results indicate that all drawn contour parts optimally fit along a single prototype linear spiral with fitting error of less than 0.4mm, supporting existence of a very advanced culture for the era of geometric guide. It is statistically rejected that this guide could have the form of a stamp. Moreover, there is strong evidence that the painter might have used a draft plan of the spiral themes to prepare the final drawing and that the linear spiral guide has been used by alternating its placements in order to form the internal and external spiral contour.