During the eighties and nineties, several thousands original photographic plates had been digitized with the MAMA microdensitometer and calibrated to meet the specific objectives of a number of national and international projects in a variety of scientific domains: clusters of galaxies, samples of quasar candidates, young stellar objects, variable stars, stellar populations in the solar neighbourhood, tidal effects on open and globular clusters, microlensing. More recently, our team (Observatoire de Paris) has undertaken digitizing and making available to the astronomical community three atlases: ESO-R and southern part of POSSI-E in the R band, SRC-J in the B band. Original acknowledgement for data: The project is conducted in partnership with the VO Paris Data Centre and the ALADIN group (CDS).