Historian and compiler of Italian saint iconography. Kaftal was raised in Russia. At the Bolshevik revolution, he fled across the snows of Russia initially to Paris, where many émigrés fled. There he worked briefly as a stockbroker, then studied for the preisthood before moving to Florence in the 1930s. In Italy, he devoted himself to the systematic study of the iconography of Italian saints.

Specialist in classical Greek and Roman art, particularly pottery and ceramic painting. Assistant to Ludwig Curtius at the deutsches archäologisches Institut (German Archaeological Institute, or DAI) in Rome 1929-1932. Taught at the University of Freiburg i.Br. from 1932-1941, towards the end as ausserordentlicher Professor. In 1936 Technau was selected to write the volume on the Greek pottery painter Exekias for the Bilder griechischer vasen series edited by J. D. Beazley and Paul Jacobsthal.