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 002 is based on Transport for London’s emails from January to March 2013, regarding information on security cameras and state surveillance.