“I would love to support you with my know-how, my huge wealth of experience and plenty of enthusiasm for your project. I can attend to your wishes very flexibly and discretely – and rest assured: I will deliver superb results, even for smaller budgets.”
Annette T. Keller
I am an expert in multispectral imaging and have roughly 20 years of experience in the areas of documentation and art diagnosis. Since 2000, I collaborate closely with with many institutions and museums around the world. I have been fortunate enough to have documented many internationally significant works of art. Since February 2017, I am working with Phase One to develop spectral and multispectral photographic solutions for cultural heritage and forensic investigations and machine vision.
In einer nur 3-wöchigen Kunstdiagnosekampagne fotografierte ich im Museum Casa Martelli in Florenz 150 Gemälde. Wir schnürten ein Paket, das es dem Museum möglich machte, die Sammlung unter absolut gleichen Bedingungen zu erfassen und den Zustand der einzelnen Gemälde unter konservatorischen Gesichtspunkten zu analysieren.
Technique
Process:
Alle Gemälde unterschiedlichster Maltechniken, Trägermaterialien (Holz, Leinwand, Papier, Metall) und Formate wurden von mir dokumentiert und diagnostiziert. Die Dokumentation erfolgte mit diffuser Beleuchtung und im Streiflicht. Zur Kunstdiagnose nutzte ich die Infrarotfotografie und die Ultraviolett Fluoreszenztechnik. Die Infrarot Falschfarbenbilder wurden nach der Kalibrierung der Aufnahmen elektronisch am Computer erstellt. Alle Aufnahmen entstanden unter absolut gleichen Bedingungen und lassen sich so eindeutig “vergleichen” und analysieren.
Equipment
Camera:
MamiyaLeaf Aptus 6 micron pixelsize, 16bit Farbtiefe, ISO 50, RAW-Format
Lens:
Schneider-Kreuznach
Software for Capture and Editing:
CaptureOne Professional
Color Reference:
Labsphere Spectralon und Colorchecker
Computer and Monitor:
Macbook Pro, Formac HighEnd-Monitor 23”, Kalibrierung mit xRite Sonde
Opificio delle Pietre Dure, Florenz und Comune di Milano, Mailand
Year of the project:
2006-heute
Specifics:
Das “monocromo” von Leonardo da Vinci dokumentierte und diagnostizierte ich mit den Methoden des multispectral imaging sowohl im Stitching Verfahren als auch durch Einzelaufnahmen. Bisher wurden vier Kampagnen von mir begleitet. Mehr Informationen finden Sie in diesem Interview.
Technique
Process:
Das “monocromo” habe ich seit Dezember 2013 mehrfach dokumentiert und diagnostiziert. Die Dokumentation erfolgte unter diffuser Beleuchtung. Zur Kunstdiagnose nutzte ich die Ultraviolett Fluoreszenztechnik. Ich setzte Speziallampen ein, die auf Grund von Spezialfiltern der Firma Schott (DUG11) jegliche Emission im sichtbaren Bereich blockieren und somit den nicht erwünschten hohen Blauviolettanteil eliminieren. Auf der website www.saladelleassecastello.it finden Sie eine Übersicht über die bislang durchgeführten verschiedenen Untersuchungskampagnen seit Beginn des Projektes.
Equipment
Camera:
MamiyaLeaf Aptus 6 micron pixelsize, 16bit Farbtiefe, ISO 50, RAW-Format
Lens:
Schneider-Kreuznach
Software for Capture and Editing:
CaptureOne Professional
Color Reference:
Labsphere Spectralon und Colorchecker
Computer and Monitor:
Macbook Pro, Eizo HighEnd-Monitor 23”, Kalibrierung mit xRite Sonde
Lighting:
Broncolor Flash-3200 Watt Generator, Beleuchtung mit Emission in Infrarot, UV Speziallampen mit Schott DUG11 Filtern
Gabinetto dei Disegni, Castello Sforzesco, Mailand
Client:
Guggenheim Museum and Foundation, New York
Year of the project:
2013
Specifics:
Um Boccionis Werke kunsthistorisch eingehend zu studieren und zu analysieren, wurden alle Werke der Sammlung in Mailand unter exakt gleichen Bedingungen diagnostiziert. In nur einer Woche realisierte ich die Aufnahmen vor Ort mit einem an die Gegebenheiten angepassten Setup.
Technique
Process:
Alle Zeichnungen habe ich dokumentiert und diagnostiziert. Die Dokumentation erfolgte unter diffuser Beleuchtung. Zur Kunstdiagnose nutzte ich die Infrarotfotografie und die Ultraviolett Fluoreszenztechnik. Die Infrarot Falschfarbenbilder wurden nach der Kalibrierung der Aufnahmen elektronisch am Computer erstellt. Um die Kunstwerke nicht durch UV Strahlung zu beschädigen, arbeitete ich mit UV-Blitztechnologie und Blitzzeiten von Millisekunden. Die Spezialkalotten der Blitzköpfe blockieren jegliche Emission im sichtbaren Bereich und somit den nicht erwünschten hohen Blauviolettanteil.
Equipment
Camera:
MamiyaLeaf Aptus 6 micron pixelsize, 16bit Farbtiefe, ISO 50, RAW-Format
Lens:
Schneider-Kreuznach
Software for Capture and Editing:
CaptureOne Professional
Color Reference:
Labsphere Spectralon und Colorchecker
Computer and Monitor:
Macbook Pro, Formac HighEnd-Monitor 23”, Kalibrierung mit xRite Sonde
2018-2021 I am proud to have played a key role in the development of the fully automated Phase One Rainbow Multi & Narrowband Imaging solution. Image sequences from UV to infrared, so-called stacks, are generated in the highest resolution at the push of a button, perfectly calibrated and repeatable. Multiband recordings are supplemented by narrow band stacks (16 recordings) and become the link between imaging and science. Reading out spectra and PCA and ICA algorithms opens up further non-invasive application possibilities.
2019-2021 Support of the preservation project of the Swiss National Museum for the investigation of the Strappi and Stacchi from Müstair as well as the existing stock in Müstair Monastery St. Johann by means of spectral multiband photography
2017-2018 Research on the differentiation of white pigments by means of spectral imaging
2017-2018 Multispectral Imaging analysis in Müstair, Stiftung St. Johann, UNESCO World Heritage
Since 2017 Development of spectral and multispectral photographic solutions for cultural heritage and forensic investigations together with Phase One, Consultant CH activity
2015-today Lecturer at the State Academy of Fine Arts in Stuttgart
2008–2013 Producer for the video projects “Gianna Nannini incontra Raffaello”, “Christina Lissmann incontra Andrea Mantegna”, “Il Caprotti di Caprotti”
2008–today Training sessions on the subject of multispectral imaging, including: 2017 at three police offices in three German federal states, 2013 Associazione laboratorio di diagnostics in Spoleto at the University of Perugia, 2008 Rathgen research laboratory in Berlin and 2005– 2006 digital imaging and calibration standards at the Kunsthistorisches Institut (Max-Planck-Institut) in Florence
2000-2018 Freelance work, Opificio delle Pietre Dure in Florence, development of UV false colour photography together with Alfreso Aldrovandi, Ezio Buzzegoli and Diane Kunzelman
2004–2006 Teaching scientific photography at the Opificio delle Pietre Dure in Florence
Selection of my partners
I love the diversity of my projects and the excitement of collaborating with various partners. A selection:
Opificio delle Pietre Dure, Cecilia Frosinini and Alfredo Aldrovandi
Cecilia Frosinini Ministero per i Beni e le Attività Culturali Opificio delle Pietre Dure – Firenze Storico dell'Arte direttore coordinatore Direttore del Settore restauro pitture murali
Direttore del Settore restauro disegni e stampe
Vice-Direttore del Settore restauro dipinti mobili 18 August 2014
Alfredo Aldrovandi Ministero per i Beni e le Attività Culturali Opificio delle Pietre Dure – Firenze Fisico Direttore Coordinatore Responsabile per le indagini diagnostiche non invasive su opere d’arte Responsabile dei servizi di documentazione 1 June 2014
Cecilia Frosinini: The Opficio delle Pietre Dure has already been collaborating with Annette Keller since 2000. A long and highly productive period that has brought forth intersections between various competencies and consequently significant results in the area of imaging technologies in art diagnosis. I would like to give a few examples of this interaction to highlight the complexity of the diagnosing process and the notable part it plays in research, namely discovering the techniques employed in the creation of a work of art and unearthing its history. The first example is the discovery of how to use the properties of UV reflection. By combining UV reflection with a congruent exposure made in visible light and subsequently manipulating the image into a virtual rendering – the so-called UV false colour image – we can easily differentiate between pigments, especially modern ones. For this project to succeed, it was essential that the physicist Alfredo Aldrovandi, the restorer Enzio Buzzegoli, both employed at the Opificio delle Pietre Dure, and Annette Keller collaborated closely. Another example: the UV fluorescence photo campaign of the mural paintings by Giotto in the Cappella Peruzzi in the Santa Croce Church in Florence. In 2009, the Opificio delle Pietre Dure proposed to the Getty Foundation to undertake a scientific art diagnosis project that would examine the technique that Giotto employed to create the mural paintings in the Santa Croce Church in Florence. The artist’s two Florentine masterpieces in the Cappella Bardi and the Cappella Peruzzi were to be analysed. Right at the start of the project and the evaluation of the first non-invasive diagnosis results, we realised that the UV fluorescence photography technique made the nearly invisible mural paintings clearly visible again, in fact, it made them appear almost three-dimensional. This discovery immediately aroused the interest of scientists studying Mediaeval art. By making the mural in the Cappella Peruzzi visible again with ultraviolet fluorescence exposures, new insights for the interpretation of Giotto’s piece could be gleaned. This is one of the greatest discoveries of the past decades in terms of research into Giotto’s works. It enabled a more accurate dating and a better understanding of the artist’s hitherto obscure later period.
Alfredo Aldrovandi: Knowing that we can produce a scientifically relevant result in terms of art history has led the Opificio delle Pietre to initiate a global project named “Giotto Segreto”. Aim of the project was to make paintings that have disappeared over time visible again – for scientists and experts but also to make this extraordinary discovery visible to the wider public. By collaborating with Annette Keller and thanks to the funding by the Harvard Center for Renaissance Studies Villa I Tatti (Florence), the Opificio delle Pietre Dure was able to realise a photo campaign that documents the entire Cappella Peruzzi in UV fluorescence lighting. The exposures were made in the highest possible resolution using the stitching method and were subsequently assembled. An extremely complex method due to the great number of single exposures and the difficulty of creating truly homogenous lighting. Within the next two years – once the scientific volume has been published – the results will be made available to the public via the Harvard University website. Here, the project will be presented from every angle: historically, art historically, photographically.
Francesca Rossi Responsabile del Gabinetto dei Disegni Civiche Raccolte Grafiche e Fotografiche Castello Sforzesco - Milano Conservatore 20 August 2014
Annette T. Keller – in 2013, on behalf of the Milan council and the management at the Musei del Castello Sforzesco, artimaging has completed a project using optoelectronic multi-spectral exposures in maximum resolution. A total of 61 drawings by Umberto Boccioni (1882-1916) at the Civico Gabinetto dei Disegni del Castello Sforzesco were examined. The exposure techniques employed were: exposures in diffused light, infrared exposures (950 nm), infrared false colours and ultraviolet fluorescence exposures. The exposures are currently being evaluated at the Gabinetto dei Disegni del Castello Sforzesco in collaboration with the Opificio delle Pietre Dure, Settore Materiali Cartacci e Membranacci, Florence. The imaging project was sponsored by the Solomon R. Guggenheim Museum and Foundation, New York.
Monica Bietti Ministero dei beni e delle attività culturali e del turismo Soprintendenza Speciale per il Patrimonio Storico Artistico ed Etnoantropologico e per il Polo Museale della Città di Firenze Director of the museum Casa Martelli 27 May 2014
We hereby certify that, in September 2013, Ms Annette Keller completed a photo project to document and produce a multi-spectral art diagnosis of the paintings at the museum Casa Martelli.
In order to study the conditions of the works of art, possible earlier changes / restorations and the techniques employed by the painters, the approx. 150 works were captured and analysed with the diffused light, infrared, UV fluorescence and infrared false colour methods. This is essential groundwork, enabling further studies of each individual work.
The imaging process was performed with great competence and professionalism and was completed both in the way previously arranged and within the scheduled timeframe. The data – carefully ordered and complete with colour calibration standards for further scientific evaluation – was handed over, as agreed, in February 2014.
Having surveyed her competencies, I can confirm that Ms Annette Keller is one of the most professional and skilled people available for this kind of documentation.