Fleming and Bergström treat the Stockholm Public Library not as a fixed canonical object but as an unstable evidentiary field reconstructed across archival plans, committee records, later alterations and contemporary 3D scanning. The central operation is epistemic translation: incomplete historical drawings are compared with subsequent physical change and with a new point-cloud record capable of documenting the building at unprecedented resolution. The paper shows that architectural knowledge is never simply recovered; it is produced through the coordination of heterogeneous representational regimes. A drawing records an intention, an alteration records use and institutional history, while laser scanning records present geometry without automatically explaining its provenance. Their combined method converts gaps in the archive into research questions rather than defects to be concealed. The wider significance lies in the relation between heritage studies, digital documentation and architectural history: new media do not merely preserve old buildings, but reorganise what can be compared, verified, taught and acted upon. Representation becomes an active instrument in the building’s continuing life.