Sun-Shadow Areas on Raised Relief in Extreme Raking Light Conditions Provided by Reflectance Transformation Imaging

May 4, 2021

In this next installment of the "Let's Talk About…" series, digitalEPIGRAPHY puts relief representation under the microscope. Relief (from the Latin relevo, to raise), by its definition, is a sculptural technique where the sculpted elements remain attached to a solid background of the same material.

Typically, ancient Egyptian reliefs are either raised from (bas) or sunken into (en creux) the surface, sometimes the two techniques combined within a single scene. In their physical existence, decorative elements carved in relief utilize the third dimension. Beginning with the first epigraphical efforts in Egypt, it has been a natural desire to capture this attribute on a sheet of paper with only two aspects: length and breadth.

On paper, relief is characterized by an outline drawing of various line weights. In this artificial environment, the theoretical light source is placed at the upper left corner, raking the surface elements at a 45-degree angle. According to the Chicago House method, bas relief is drawn with thinner lines at the upper left and thicker lines at the lower right side, with the conventions reversed for elements carved in sunk relief. The exact rulebook of representing carved features in a two-dimensional environment can be found in the Digital Epigraphy Manual.

Although rooted in the physical appearance of the actual carved elements, the Survey's sun-shadow system is by no means the exact derivative of the relief's realistic projection onto the wall. If you'd like to know more about how shadow is studied and represented using digital tools, read the full article here! Cover RTI image by Hilary McDonald.

This post was originally released as part of digitalEPIGRAPHY's growing Instagram collection. If you'd like to see our latest photos as soon as we post them, please follow us on Instagram.

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