Film Restoration

We have proposed an alternative approach to the standard digital film restoration, based on the idea of recovering the appearance of color rather than the original color signal. Since in many cases physical color restoration is not possible due to the lack of original reference or to severe gamut constraint induced by non available original media, the described approach is based in the application of Spatial Color Algorithms (SCAs).

PhotoFire2


Among the great variety of our Cultural Heritage, photographic and cinematographic materials are fundamental and direct witnesses of the past. The classification and restoration of these materials are often needed as they can undergo severe deterioration, aging and colour fading. They also have to keep up with the quick technological changes. For instance, over the years the film industry has faced a lot of innovations in many fields, such as the development of different film base materials, the advance of many acquisition and projection instruments as well as printing and developing machines and the introduction of different colouring techniques. In this context, it is fundamental to analyse, study and understand the chemical and physical composition of the different films, to set up restoration workflows which are faithful to the original materials also employing modern acquisition and fruition instruments.
The lack of technical information and the absence of open-source archives of the production companies, underlines the actual and concrete need of a database of physical, chemical and sensitometric data of films and photos. A special attention is given to the retrieval of colorimetric information.
The aim of this work is the creation of a unique big database and an online open-source dataset of cinematographic and photographic materials, to support the work of conservators, restorers and researchers. Everyone will be able to access the website and every material will be free to consult and download. Moreover, everyone in possession of useful material will have the chance to help expand and upgrade the database, by uploading them in the dedicated section after a further supervision.
The creation of an open-source database for the sharing of knowledge is of great importance, as the availability of information is essential for the preservation of our Cultural Heritage.

Website created by Arianna Crespi and Giulia Morabito , database developed by Arianna Crespi .
Database link: https://mips.di.unimi.it/photofire/


Unsupervised Digital Movie Restoration with Spatial Models of Colors


Since its invention in the nineteenth century, cinema has become one of the most important media of popular culture, becoming in fact, next to the books, our historical memory. Unfortunately, color films are subject to the aging of dyes contained in the emulsion and of the support itself. The decay is a natural process that usually introduces a color dominant, loss of contrast and/or color desaturation. Color negative and positive film, color print material, interpositives, and color motion-picture release print are all affected in the same way. The decaying process is irreversible, and the most effective method to slow it is to store photographic and cinematographic material at controlled temperature and humidity. It has been estimated that about 80% of the movies produced between 1910 and 1920 have been lost. If not restored, a large part of the film cultural heritage will be lost relatively quickly. Hence the strong ethical obligation to preserve and restore those moving images that represent our social memory. Thanks to the relevant technical progresses of the last years, the digital restoration of color has widely spreaded. Digital techniques allow an easier removal of color casts, equalization of the frame histogram, expansion of the dynamic range and adjustment of desaturated colors. Moreover, it can address artifacts not treatable by traditional photochemical techniques. Finally, digital techniques allow easily multiple attempts, however, constant supervision by qualified personnel is still required. Moreover, a digital pipeline can address effectively the scaling of the restored content to the different formats and gamuts, necessary for the multiple different visualization devices currently available in cinemas. Current state of the art in digital restoration is mainly based on color grading techniques: "primary" grading affects the levels of RGB, gamma, shadows and highlights in the entire frame, while "secondary" techniques apply changes only on a selected range of colors or windows in the frame. We have proposed an alternative approach to the standard digital color film restoration, based on the idea of recovering the appearance of color rather than the original color signal, by means of the application of Spatial Color Algorithms (SCAs), a family of algorithms inspired by the capabilities of the Human Vision System (HVS) of autonomously adjust to the variation of color and lightness in the scene. <\br> Further information on the algorithms used to enhance digital images can be found in section Image Enhancement.

Showreels

Publications


Books

Alice Plutino, “Tecniche di Restauro Cinematografico – Metodi e Pratiche tra Analogico e Digitale”, Manuali n. 244, Dino Audino Editore, ISBN: 9788875274672, 2020.

Journal Papers

A. Plutino, A. Rizzi, “Research directions in color movie restoration”, Coloration Technol, Volume 137, Issue 1, Special Issue: Challenges and Open Problems in Colorimetry Special Issue, February 2021, Pages 78-82, DOI: https://doi.org/10.1111/cote.12488.

Plutino A., Lanaro M. P., Liberini S. and Rizzi A., “Work Memories in Super 8: searching a frame quality metric for movie restoration assessment”, journal of Cultural Heritage 41 (2020): 238-248, DOI: https://doi.org/10.1016/j.culher.2019.06.008.

A. Rizzi, A. Berolo, C. Bonanomi, D. Gadia, “Unsupervised Digital Movie Restoration with Spatial Models of Color”, Multimedia Tools and Application, First online: July 2014, ISSN 1380-7501, 75:7 (2016 Apr), pp. 3747-3765, DOI: https://doi.org/10.1007/s11042-014-2064-5.

A. Rizzi, M. Chambah, “Perceptual Color Film Restoration” SMPTE Motion Imaging Journal (Society of Motion Picture and Television Engineers), Vol. 19, No 8, pp. 33-41, Nov-Dec, (2010), DOI: https://doi.org/10.5594/J17295.

Book Chapters

S. Bellotti, G. Bottaro, A. Plutino and M. Valsesia, “Mathematically-Based Algorithms for Film Digital Restoration”, Imagine Math 7 - Between Culture and Mathematics, Pages 89-104, edited by Michele Emmer and Marco Abate, Springer. ISBN 978-3-030-42653-8

A. Plutino and A. Rizzi, “Alternative Methods for Digital Contrast Restoration”, Imagine Math 7 - Between Culture and Mathematics, Pages 73-87, edited by Michele Emmer and Marco Abate, Springer. ISBN 978-3-030-42653-8

A. Plutino, A. Rizzi, "Algorithms for Film Digital Restoration: Unsupervised Approaches for Film Frames Enhancement", Moving Pictures, Living Machines, Eds. Greta Plaitano, Simone Venturini, Paolo Villa, MIMES International, pp. 265-272, ISBN 9788869772764, 2020.

A. Rizzi, B. Barricelli, C. Bonanomi, A. Plutino, M.P. Lanaro, “Spatial Models of Color for Digital Color Restoration”, in Conservation, Restoration, and Analysis of Architectural and Archaeological Heritage, Eds C. Inglese, A. Ippolito (2018) ISBN13: 9781522575559.

A. Rizzi, C. Gatta, C. Slanzi, G. Ciocca, R. Schettini, “Unsupervised Color Film Restoration Using Adaptive Color Equalization”, Lecture Notes in Computer Science, Volume 3736, Dec 2006, Pages 1 – 12

Conference Proceedings

A. Plutino, M. Lecca, A. Rizzi, “A Cockpit of Measures for Image Quality Assessment in Digital Film Restoration”, International Conference on Image Analysis and Processing (pp. 159-169). Springer, Cham, September 2019, DOI: https://doi.org/10.1007/978-3-030-30754-7_16.

I. Otto, A. Plutino, M.P. Lanaro, A. Rizzi, “All the Colours of a Film: a study on the Chromatic Variation of Movies”, AIC Lisboa 2018 - AIC Interim Meeting - 25–29 September 2018, Lisbon (Portugal).

A. Plutino, M. Lanaro, A. Ghiroldi, R. Cammarata, A Rizzi, “Work Memories in Super8: the dawn of paper recycling in Brescia”, VI International Conference YOCOCU, May 22-26th 2018, Matera, (Italy).

A. Plutino, M. Lanaro, A. Ghiroldi, R. Cammarata, A Rizzi, “ACE for Super 8 movie restoration”, Mathematics for Computer Vision (MCV 2018) February 15-16th 2018, Trento, (Italy).

Papers on national journals and proceeding

L. Cristina, A. Plutino and A. Rizzi,"I colori del viaggio dell'eroe: uno studio degli archetipi nei film", A Conservation Carol - 18th December 2020, http://conservationcarol.di.unimi.it/proceedings2020.html.

A. Cairoli, A. Plutino and A. Rizzi, "Un protocollo di digitalizzazione per i negativi della sotto-serie "Cinema" del fondo "La Notte"", A Conservation Carol - 18th December 2020, http://conservationcarol.di.unimi.it/proceedings2020.html.

A. Berolo, D. Sabatini, C. Bonanomi, D. Gadia, D. Marini, A. Rizzi, "Il restauro del colore digitale: un approccio basato sull’apparenza", Cultura e Scienza del Colore - Color Culture and Science, N. 1, pp. 8-12, 2014.