In Ancient Greece, architecture and sculpture were painted. Nevertheless, the appearance of the colors used to decorate buildings remains largely unknown due to lack of evidence. The Temple of Apollo at Delphi, is no exception to this situation. Since its discovery in 1894, the question of polychromy has been partially studied. This situation can be explained by the difficulty of detecting pigments directly on the ancient blocks by simple visual observation. The majority of them are imperceptible to the naked eye. This paper aims to put a exploratory methodology based on archaeometric, photogrammetric and computer analyses in order to the locate, characterize traces of polychromy that are invisible to the naked eye and to provide new data that can be used to reconstruct the architectural polychromy of the Temple of Apollo at Delphi in the late classical period.