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

Catelli, Emilio (author), Liu, Lingxi (author), Fadanni, Jacopo (author), Stergar, Jošt (author), Milanič, Matija (author), Sciutto, Giorgia (author), Zerbetto, Francesco (author), Prati, Silvia (author)

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.

• Language: English
• Keywords: color films, digital restoration, hyperspectral imaging, cluster-based spectral correction algorithm, CBSCA
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FMF - Faculty of Mathematics and Physics
• Publication status: Published
• Publication version: Version of Record
• Year: 2026
• Number of pages: Str. 12511-12523
• Numbering: Vol. 16, iss. 14
• PID: 20.500.12556/RUL-181116
• UDC: 004.9:791.53
• ISSN on article: 2046-2069
• DOI: 10.1039/D5RA08504G
• COBISS.SI-ID: 273009411
• Publication date in RUL: 25.03.2026

Record is a part of a journal

• Title: RSC advances
• Publisher: RSC Publishing
• ISSN: 2046-2069
• COBISS.SI-ID: 2513252

Licences

• License: CC BY-NC 3.0, Creative Commons Attribution-NonCommercial 3.0 Unported
• Link: http://creativecommons.org/licenses/by-nc/3.0/
• Description: You are free to reproduce and redistribute the material in any medium or format. You are free to remix, transform, and build upon the material. You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use. You may not use the material for commercial purposes. You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits.

Secondary language

• Language: Slovenian
• Keywords: barvni filmi, digitalno restavriranje, hiperspektralno slikanje, CBSCA algoritem

Projects

• Funder: Other - Other funder or multiple funders
• Project number: SI18MO03
• Name: Advanced imaging technologies for the study of works of art