Rediscovering lost colors: film color restoration by hyperspectral imaging and cluster-based spectral correction algorithm (CBSCA).

The present study proposes a new method for the digital restoration of color films affected by irregular color degradation. Color fading is a major problem affecting analog color films and while most existing digital methods address homogeneous dye fading, the correction of irregular color degradation remains a challenging and time-consuming process. The main objective of this work is to develop a scalable and minimally user-guided strategy capable of restoring such complex degradation patterns. The proposed approach combines visible-range hyperspectral imaging of degraded film frames to obtain detailed spectral information with a novel computational algorithm referred as the Cluster-Based Spectral Correction Algorithm (CBSCA). This algorithm is specifically designed to handle the large volume of data recorded by hyperspectral acquisition, enabling robust color restoration while ensuring reduced computational demand and limited subjective intervention. In comparison with conventional RGB scanners and color restoration software, this approach offers a methodology to perform accurate color acquisition and correction while effectively managing large hyperspectral datasets. The ultimate goal is to recover the film's original visual content, ensuring its accessibility to the public.