With the advent of open data initiatives, raw data has been staged as a crucial element of government transparency. If the consequences of such data-driven transparency have already been discussed, we still don’t know much about its back rooms. What does it mean for an administration to open its data? Following information infrastructure studies, this communication aims to question the modes of existence of raw data in administrations. Drawing on an ethnography of open government data projects in several French administrations, it shows that data are not ready-at-hand resources. Indeed, three kinds of operations are conducted that progressively instantiate open data. The first one is exploration. Where are, and what are, the data within the institution are tough questions, the response to which entails organizational and technical inquiries. The second one is extraction. Data are encapsulated in databases and its release implies a sometimes complex disarticulation process. The third kind of operations is ‘rawification’. It consists in a series of tasks that transforms what used to be indexical professional data into raw data. To become opened, data are (re)formatted, cleaned, ungrounded. Though largely invisible, these operations foreground specific ‘frictions’ that emerge during the sociotechnical shaping of transparency, even before data publication and reuses.