Abstract: Print is one of humanity’s most impactful technologies, yet much of its origins remain unclear, particularly surrounding the earliest instances of moveable metal type print. While there is documentation of Korean printers using metal type as early as 1234, none of the metal types used for these earliest prints have been preserved and their metal compositions remain unknown. Even fewer technical details are known about the first European metal type press invented by Johannes Gutenberg in the mid 15th century, despite its major role in launching the Renaissance period in Europe by revolutionizing Western information dissemination. Working in collaboration with an interdisciplinary team of scholars, technical personnel, and scientists, my work aims to fill in the gaps in knowledge surrounding early print technology through X-ray fluorescence (XRF) imaging of early printed documents. XRF scans of around 50 early print specimens from across Korea and Europe (including an early 15th century bound Korean folio and fragments of an original 42-line Gutenberg Bible) as well as 7 pre-Gutenberg Arabic block prints revealed clear metal content only in the documents printed using metal type. Through collaboration with print scholars, I obtained and produced controlled test prints made using metal types with known alloys and nonmetal inks. XRF scans of these test prints confirmed the leaching of metals from the types into the paper. Here I will present my findings and propose XRF imaging as a compelling research technique for ascertaining whether a historical document was printed using metal type and, if so, determining the metal type alloy. My work adds valuable information to scholarly studies comparing early print technologies that aims to determine whether print may have arrived in Europe from Asia.