This presentation was given by Geert Verhoeven during Session A of the goINDIGO 2022 international graffiti symposium. Project INDIGO wants to ensure the digital survival of a large part of Vienna's graffiti-scape by creating a long-term, accurate, exhaustive, open access and interactive online archive. The digital photographs of graffiti constitute one of the archive's main backbones. Not only do they represent the spectral and spatial data about every graffito, but they are also used to extract the three-dimensional surface geometry needed to turn these photographs into colour-accurate, distortion-free orthophotographs. That is why INDIGO photographs are taken according to specific rules and with dedicated hardware. This talk will explain the rationale of INDIGO's photographic approach and detail the entire photo acquisition process: from the logistics for the bi-annual total coverage surveys (targeting the whole research area) to the camera settings and newly developed hardware for the bi-weekly photo tours (aiming to record new graffiti). The presentation will expand on INDIGO's current reliance on human memory and social media combined with specific apps to keep track of must-record changes in the graffiti-scape. However, the talk also reviews plans for a more automated change detection approach. Overall, this contribution wants to clarify that photographs, whether of graffiti or any other form of cultural heritage, typically serve a specific purpose. To reach that purpose, photographs should usually be more than mere snapshots. Via this talk's focus on INDIGO-specific photography strategies and hardware, the INDIGO team hopes to get critical feedback, valuable suggestions and collaboration proposals. These would benefit everybody involved and ideally lead to the joint development of more dedicated photo acquisition workflows for any cultural heritage recording or monitoring project.

The INDIGO graffiti project is funded by the Heritage Science Austria programme of the Austrian Academy of Sciences (ÖAW)