MuseumDigit 2019 Budapest lecture Multispectral Imaging & technical photography Annette T. Keller

Making the invisible visible

Lecture at the MuseumDigit 2019, 27. November, Budapest

Development in Multispectral Imaging and the technical photography. How can we restore the readability of a damaged document? How is it possible to make the invisible visible, to see the tiniest details and material destination of an object? Capturing Images only once in the highest resolution possible. The automated process enables the research into the materials, pigments, bindings, retouching and underdrawings. Moreover, Multispectral Imaging is an analytical tool that delivers important information about an object and can guide other investigations, thanks to multi- and narrowband Image informations.

Vatican Museums workshop multispectral photography Annette T. Keller

MSI Workshop in the Vatican

Multispectral Imaging

The application of multispectral photography was the focus of the three-day workshop. Phase One High End technology was used. The 150MP BSI Digitalback in a modified version integrated into a multi-spectral package developed together with Phase One, consisting of camera, digital back, lighting, filters and targets, mobile and modular and therefore perfectly suitable for use in a museum context.

project of the Swiss National Museum for the investigation of Strappi and Stacchi from Müstair spectral photography Annette T. Keller

Conservation Project Swiss National Museum

Spectral Multiband Photography

To support the conservation project of the Swiss National Museum for the investigation of Strappi and Stacchi from Müstair, currently in the Swiss National Museum, as well as the still present in Müstair monastery stocks, I photographed in September and October the wall paintings in reflectance and photo-induced luminescence.

St. Prokulus, Naturns spectral photography Annette T. Keller

Proceedings & Museum Guide St. Prokulus

Interim report on spectral photography in St. Prokulus

My summary of the observations of the ongoing non-invasive analyzes using spectral photography in St. Prokulus, Naturno, between December 2017 and June 2018. The church is dedicated to Saint Bishop Prokulus of Verona. As the investigations are still in their infancy, no final evaluation of the results is possible at the present time.

Lecture at the symposium 2019
 “forensic photography”

The focus of my presentation was the new development, together with Phase One, for the automated digital capture of objects and materials in the multi-band and narrowband range to the max. Optimization of repeatability and investigation of materials of interest to crime technology.


artIMAGING conservation analysis project of two Pieter Bruegel masterpieces: The Strife Of Lent and Winter Scenery

A conservation analysis project of two Pieter Bruegel masterpieces

Study of The Strife Of Lent and Winter Scenery

The project was carried out by Loa Ludvigsen, Anne Haack Christensen and Jørgen Wadum from SMK in Copenhagen, and supported by me, as the Phase One´s Multispectral Imaging specialist. The equipment used was a Phase One XF IQ3 100MP Camera System, filters and LED lights. The kit was designed to deliver a stack of images according to the Charisma manual (British Museum 2013), that allows for analysis of different components of the paintings.


artIMAGING Article in the Journal of Cultural Heritage: Mainly red and a hidden blue - Laboratory and MSI investigations on the Carolingian wall painting in the Chapel of the Holy Cross of Müstair, Switzerland

Article in the Journal of Cultural Heritage

Mainly red and a hidden blue - Laboratory and MSI investigations on the Carolingian wall painting in the Chapel of the Holy Cross of Müstair, Switzerland

was published in August. Together with Christine Bläuer (CSC Sàrl), in this article I have referred to scientific investigations connecting multispectral photography using the example of the UNESCO World Heritage Site in Müstair (CH).



artIMAGING Multispectral Imaging & avant-garde


Painting study in Bulgaria

In August, I studied ten paintings in Sofia using multispectral imaging. Particularly interesting here was the differentiation of the white pigments titanium white rutile and titanium white anatase, as they appeared at different times on the art market and thus can make an assignment of the artworks possible. At the end of the year, an article in Conservation 360 ° will be published on details of the recording procedures leading to the differentiation of rutile and anatas, published together with Prof. Roland Lenz of the State Academy of Fine Arts Stuttgart and colleagues from Politecnico di Milano and the University of Gothenburg.

artIMAGING Spectral Multiband Imaging UNESCO World Heritage Saint John Abbey, Müstair

Spectral Multiband Imaging

Unesco World Heritage Saint John Abbey, Müstair

In the summer of 2018, the conservation work of the mural paintings in the middle apse in the monastery of St. John in Müstair began. In summer of 2019 I repeated the already recorded areas with spectral multiband photography to document restoration work. We were able to make interesting conclusions regarding the pigment Egyptian blue.

artIMAGING lecture at the the 2+3D conference Amsterdam

2+3D Photography


During the 2+3D conference I gave a lecture together with Phase One on the topic of multispectral photography. I talked about technical details as well as the practical application of the non-invasive procedure. My colleagues from Phase One presented the technical developments of automation in the field of multispectral photography.

artIMAGING painting analysis and MSI workshop with the City of Dusseldorf

Painting analysis and MSI workshop

City of Dusseldorf

Together with the Department of Painting of the Restoration Center of the City of Dusseldorf I examined two paintings by Angelika Kaufmann in the Kunstpalast in May. The multispectral photography provided i.a. Information on pigment distribution, conservation status and painting technique. This was followed by a three-day workshop on painting/contemporary art, wood/design, ceramics, photography, paper and arts and crafts.

artIMAGING Lecture at the Ecole des sciences criminelles, Lausanne

Lecture at the Ecole des sciences criminelles


Multispectral photography has a long tradition in forensic analysis. Together with Phase One, I presented innovative solutions for the realization of spectral images with a high degree of automation, using practical examples.

artIMAGING Stamp analysis with the Staatlichen Akademie der Bildenden Künste Stuttgart

Stamp analysis

Staatliche Akademie der Bildenden Künste Stuttgart

In April I examined together with the Staatlichen Akademie der Bildenden Künste Stuttgart a selection of stamps on their abnormalities and similarities, conservation status and pigment distribution. The results will be summarized in a master thesis in autumn.

artIMAGING is an ICOM (International Council of Museums) member

Icom member Artimaging

As a member of the International Council of Museums, I am committed to the preservation, care and communication of the cultural and natural world heritage. ICOM has more than 35,000 members worldwide and is present as an international network of museums and museum professionals across all disciplines. 119 national committees and 30 international committees as well as numerous regional and affiliated organizations belong to ICOM.

Mantegna and Bellini

On the occasion of the exhibition in the Gemäldegalerie in Berlin my video production Christina Lissmann incontra Andrea Mantegna from the series "The guided view" with music by the composer Nils Frahm gets even more topical.

watch the video

artIMAGING Multispectral Imaging workshop at the Bibliotheca Hertziana, Rome

Multispectral Imaging workshop

Bibliotheca Hertziana, Rome

At the Max Planck Institute for Art History, the Bibliotheca Hertziana, I conducted a workshop on multispectral photography. We looked at ancient writings and paintings at different wavelengths to improve readability, get information on painting techniques, and document material distribution.


artIMAGING Multispectral Imaging workshop at the Landesarchiv NRW

Multispectral Imaging workshop

Landesarchiv NRW

In order to best support the preservation of archive material, the non-invasive method is also used here. The central restoration department of the Landesarchiv NRW uses multispectral photography (infrared to UVA radiation) to document and analyze the objects.

Technical Contribution

Segni di Maraviglia

Published in summer 2019, the catalog on the history and restoration of textile objects based designed by Pollaiolo for the "Parato di San Giovanni" with my contribution to the results of the analysis by multispectral imaging.


Teaching assignment chemistry & sensitometry

Teaching assigment at Staatliche Akademie der Bildenden Künste, Stuttgart
Art history: Chemistry and sensitometry

Winter semester 2018/2019

Contribution at the symposium 2018
 “forensic science photography”

In co-operation with Phase One Cultural Heritage I talked about the development of opto-electronic multispectral imaging processes in the last two years and showed apllication examples from workshops at BKAs and LKAs.

Multiband at the Stephansdom in Vienna

In October, I examined a wall painting in St. Stephen's Cathedral in Vienna. The image information have been evaluated in collaboration with Roland Lenz, Professor of Conservation and Restoration of Wall paintings, Architectural Surfaces and Stone Polychromy at the State Academy of Fine Arts, Stuttgart.

Multispectral Imaging at SMK In Copenhagen

In August, in cooperation with SMK (Statens Museum for Art), CATS (Center for Art Technological Studies and Conservation) and Phase One, I did multispectral imaging of a Bruegel the elder Painting.

Spectral imaging in Müstair

In the summer of 2018, the conservation of the wallpaintings in the middle apse in the monastery of St. John in Müstair began. In the upper area and in the dome, in consultation with the scientific director Patrick Cassitti, I examined preservation conditions and distribution of the paint layers.

Infrared Fluorescence in St. Prokulus

In December 2017 and February & May 2018 I traveled to Naturno to study the murals in St. Prokulus. My interim report will be published in the publications of the South Tyrolean Cultural Institute, Volume 10, St. Prokulus in Naturns / San Procolo a Naturno.

Investigation in Freiburg Minster

In February and April I accompanied the studies and the conservation of the wallpainting of the Peter and Paul chapel in the cathedral of Freiburg im Breisgau. A partial area was recorded photographically in the stitching process, in high-resolution, from UV to infrared.

MSI in St. Sebaldus Church in Nuremberg

Three late-medieval, side-by-side murals that are in very poor condition due to war damage were the focus of my photography campaign. The improvement of the readability of the depicted scenes played a role as well as the investigation of references to the restoration history.


Piero della Francesca Conservation

At the end of March, the masterpiece Piero della Francesca The Resurrection was presented. At the end of the restoration, at the end of February, I documented the artwork for the last time in visible light and with specially selected wavelengths in the stitching process.

MSI in Weimar

On behalf of the Klassik Stiftung Weimar I examined fire-damaged documents with charred edges using spectral and multispectral photography. The focus was on the readability of the font.

Profane room settings from 13th century

A test project investigating decorative paintings using spectral photography took me to Erfurt. There I photographed remnants of a former color version in the " Raum mit der Blütendecke" commissioned by the University of Applied Sciences Erfurt.

Teaching assignment chemistry & sensitometry

Teaching assigment at Staatliche Akademie der Bildenden Künste, Stuttgart
Art history: Chemistry and sensitometry

Winter semester 2017/2018

Multispectral Photography

My 3-5-day workshops focus on the application of multispectral photography in the forensic investigation. A theoretical introduction is followed by practical applications and the evaluation of the image information.

Multispectral Imaging

From April to July 2017, I examined parts of the Heiligkreuzkapelle in monastery St. Johann in Müstair.

(Read more)

Teaching assignment multispectral imaging

Teaching assignment at Staatliche Akademie der Bildenden Künste, Stuttgart
. Master: Konservierung und Restaurierung von Wandmalerei, Architekturoberflächen und Steinpolychromie.

Technical Contribution

Unsichtbares sichtbar machen (making the invisible visible)

Spectral imaging, a non-invasive method.

KulturBetrieb – Ausgabe April 2017

Contribution at the symposium 2016
 “forensic science photography”

In co-operation with Phase One Cultural Heritage I talked about my work and the use of optoelectronic multispectral photographic methods in the art diagnosis and the parallels in the use of forensic investigations.


Leonardo in Francia/Léonard en France 1516–2016

is available in Italian and French language with my contribution about the Multispectral Photographie from Ultraviolett to Infrared.

Teaching assignment

Teaching assigment at Staatliche Akademie der Bildenden Künste, Stuttgart
Art history: Chemistry and sensitometry

Winter semester 2016/2017

Technical contribution

Il Caprotti di Caprotti
 Storia di un Pittore che non c’è

is now available in french language, here with my contribution about digital imaging calibration, UV fluorescence and IR false color images.

My planned contribution at the meeting Kein Berühren der Figüren

Multispectral imaging from Ultraviolett to Infrared – non-invasive examinations and the  possibilities and limits to analyze conservation state and pigments. Examples: paintings, frescos, textiles.

Meeting information & program

Multispectral Imaging

In September 2016 I accompany again the restoration of the fresco in Sansepolcro. To document the cleaning of the fresco, I use the UV fluorescence photography. Thus cleaned and uncleaned image areas are clearly visible.

Technical contribution

Ultraviolet-Induced Luminescence Imaging: Giovanni Verri, Annette T. Keller, Francesca Piquè, Alfredo Aldrovandi.

Report of the project ORGANIC MATERIALS IN WALL PAINTINGS. The Getty Conservation Institute summarizes all scientific findings and makes them available for download.

Cappella Peruzzi

From 11 December impressive UV fluorescence images of the entire Cappella Peruzzi ( Florence ) will be on display at the Palazzo Reale in Milan. The images I made during my two-month photo campaign in autumn 2012 will be showcased as multimedia installation at the Giotto, l'Italia exhibition.

Multispectral Imaging

I was highly pleased with the media coverage that commenced even before the restoration process had begun.

La Repubblica Firenze, 28/03/2015
I segreti del dipinto piu bello del mondo
Comincia dopo Pasqua il restauro della Resurrezione di Piero della Francesca a Sansepolcro.
Ma intanto la prima scoperta: l’artista ha impiegato 15 giornate d’affresco per realizzare il dipinto

The mystique of the world’s most beautiful painting
After Easter the restoration of the “Resurrection of Jesus Christ” by Piero della Francesca will begin in Sanselpolcro. Here in advance, the first finding: The artist implemented the Fresco in 15 “Giornate”.

Documentation & art diagnosis

The works of Pollaiolo take centre-stage in a running project with the Opificio delle Pietre Dure in Florence: 27 panels are being documented and diagnosed as part of the restoration process. The project will conclude in spring 2015.


Costume Colloquium IV: Colors in Fashion, Florenz

La „cartelle colore“ per il restauro ovvero i database per il riconoscimento delle tinture, e non solo, nei tessili storici: dieci anni di esperienza del Laboratorio di Restauro Manufatti Tessili dell’Opificio delle Pietre Dure di Firenze. Susanna Conti, Alfredo Aldrovandi, Bruno Radicati, Annette Keller, Marcello Melis, Licia Triolo

Technical contribution

The book “Tessuti archeologici. I frammenti copti della collezione Roca Puig. Storia e Conservazione.” on the topic of textile conservation was published in October 2014 and includes a contribution on: “Indagine sui coloranti dei frammenti della collezione Roca-Puig con la tecnica multispettrale. Una nota sulla Radiografia X”. Susanna Conti, Annette T. Keller, Isetta Tosini con la collaborazione di Alfredo Aldrovandi.


In 2013, I prepared and held a 3-day training on the topic of multispectral imaging for the employees of the Associazione laboratorio di diagnostica in Spoleto at the University of Perugia. The participants received an in-depth insight into the theory and practice, techniques and projects.

Would you be interested in a similar training? Please do not hesitate to contact me.