Seeing the invisible: ostraca hunting via multispectral imaging

Most surviving biblical period Hebrew inscriptions are ostraca (ink-on-clay texts). They are poorly preserved and might fade rapidly once unearthed. Their proper and timely documentation is therefore essential. Our study of numerous Hebrew ostraca has demonstrated that multispectral imaging has the potential to reveal letters on ostraca otherwise invisible to the naked eye. In the case of Arad Ostracon No. 16 from Judah, dated to ca. 600 BCE, we unveiled three lines of text on its supposedly blank reverse side. This surprising outcome led us to question how many ostraca we might be discarding during excavations simply because the sherds look blank. To tackle the problem, we propose a preliminary excavation protocol for screening ceramic sherds prior to disposal. The protocol is based on our limited experience rather than fully supported statistical test experiments. Here we demonstrate the application of this procedure on recently unearthed pottery sherds from the excavation at Kiriath-jearim near Jerusalem.