This work describes a collaborative experience between the School of Architecture of San Sebastián, the paint design and production company Aiadek, and the students of Graphic Expression II and III of the Degree in Technical Architecture, focused on the development of a chromatic catalog of the facades of the protected buildings of the Ensanche of San Sebastián. The initiative is part of KsiGune’s Conexiones call and is developed under a Challenge-Based Learning (CBL) and Service-Learning (ApS) strategy, promoting both architectural analysis and the conscious use of color in heritage contexts. The curricular adjustments made to integrate this work into teaching are detailed, as well as the difficulties encountered, the pedagogical benefits derived and the active involvement of students in the research process. Through a cooperative approach, materials and predominant chromatic ranges have been documented, making use of technological tools and graphic representation. The results show the relevance of color in heritage conservation and highlight the educational value of university-industry links.