The Fraunhofer Lines is a series of prints that visualizes government redactions in declassified documents obtained through Freedom of Information Act requests. Inspired by Joseph von Fraunhofer’s spectral line diagrams—which reveal gaps in light frequencies reaching Earth’s surface—Bridle uses facial recognition software to scan redacted documents, generating spectrographs that illustrate the proportion of concealed information. The dark marks that obscure text are translated into visual representations of blocked light, making absence both visible and quantifiable.

The series includes documents from various government bodies, such as the British Police, US Senate, and Dutch Air Investigation Board, highlighting the extent of institutional opacity and information suppression. Fraunhofer Lines 004 is based on Information Commissioner’s Office Reports on Police surveillance from 2008–2012. The ICO is the UK body responsible for providing oversight of and access by citizens to state information, but its own reports are heavily redacted.