Some recently published standard and new applications with the PLD

1 – Poster on MA-XRF, MS-PLD, RAMS and MSI applications on a variation of case-studies in an 8th century illuminated manuscript

Watteeuw L., Hameeuw H., Vandermeulen B., Van Bos M. (2020). The study of characteristics of an 8th century illuminated manuscript by combined use of MA-XRF and Imaging with the Multispectral Microdome. The Codex Eyckensis explored. Presented at the Cancelled due to COVID-19 ICOM-CC 19th Triennial Conference Beijing, China. Online May 2021 14–18 September 2020, Beijng. (link)

Illustration on ICOM-CC poster: “Tracing compass marks and x-y-z distances with MSMD dataset, with texture map and without, CE-A, folio 1v”

2 – Applying the PLD system to scan an entire archaeological sub-collection with a variety of artifacts

Hameeuw H., Tavernier J. (2021). La collection Proche-Orient ancien du Musée L mise en lumière. In: L. Courtois (Eds.), Les études orientales à l’Université de Louvain depuis 1834. Hommes et réalisations, (479-487). (Histoire, 12). Brussels: Éditions Safran. ISBN: 978-2-87457-124-4. (link)

on this project see also this previous blog post

3 – Study of the Medieval illuminations in the Rijmbijbel of Jacob van Maerlant manuscript, combined research with MA-XRF and MS-PLD

Watteeuw L., Van Bos M., Tatiana G., Vandermeulen B., Hameeuw H. (2020). An applied complementary use of Macro X-ray Fluorescence scanning and Multi-light reflectance imaging to study Medieval Illuminated Manuscripts. The Rijmbijbel of Jacob van Maerlant. Microchemical Journal. ( (link)

4 – Detecting under-drawings, identifying pigments, visualizing thickness pigment layers and comparing pre- and post-restoration phases

Hameeuw H., Watteeuw L., Vandermeulen B., Proesmans M. (2021). The painted panels of the early sixteenth century Mechelen Enclosed Gardens Art technical Examination with the Photometric Stereo: White Light and Multispectral Microdomes. In: L. Watteeuw (Eds.), Papers Presented at the Twentieth Symposium for the Study of Underdrawing and Technology in Painting held in Mechelen and Leuven, 11-13 January 2017: vol. 20, (165-175). Presented at the Imaging Utopia: New Perspectives on Northern Renaissance Art, Leuven, 11 Jan 2017-13 Feb 2017. Leuven. ISBN: 978-90-429-4152-6. (link)

Deciphering of Roman era lead curse tablet from Tongeren (B)

In 2016 a lead curse tablet (defixionis) was excavated in a Roman era (dated 70-275 AD) context by Aron bvba at the Regulierenplein (City of Tongeren, Belgium). A recording with the WLminiD of the Portable Light Dome system gave researchers the needed visual insights for the examination and study of this exceptional find.

Comparison on obverse of lead curse tablet based on a Portable Light Dome (White Light) recording, left: color; Right: curvature visualization.

Some publications on this lead curse tablet:

Roxanne Bélanger Sarrazin, Alain Delattre, Daniel Demaiffe, Natasja De Winter, Alain Martin, Georges Raepsaet & Marie-Thérèse Raepsaet-Charlier, avec la collaboration de Cecilia Melaerts-Saerens & Frank Scheppers, Iaô Sabaôth. Pratiques magiques dans la cité des Tongres: une tablette de défixion mise en contexte. Bruxelles, Association Égyptologique Reine Élisabeth, 2019, 120 p., fig. ISBN 978-2-9600834-5-3.r

Roxane Bélanger Sarrazin, Alain Delattre, Daniel Demaiffe, Natasja De Winter, Alain Martin, Georges Raepsaet & Marie-Thérèse Raepsaet-Charlier, Une tablette de défixion récemment découverte à Tongres, in: Latomus 78 (2019), p. 471-481, 5 fig. (see

Comparison on obverse of lead curse tablet based on a Portable Light Dome (White Light) recording, left: color; Right: sketch1 visualization.

In the press:

Some published applications on ‘Bruegel’ artwork

In the framework of the FINGERPRINT project (see also posts: Sept 25, 2019 and Sept 27, 2017) graphic artwork of Pieter Bruegel the Elder (or his circle) have been imaged and studied with the Portable Light Dome systems and/or in combination with other imaging methods. Since, some of these researches have been published:

Comparison as published in the reference below, MSMicroD, false colors,
revealing the difference in inks (collection: KBR SII132816, Luxuria)

Watteeuw Lieve, Marina Van Bos, M., Maarten Bassen, Van Grieken Joris, Currie Christina, Vandermeulen Bruno, Hameeuw Hendrik, Martens Maximiliaan 2020: Four Drawings by Pieter Bruegel the Elder: Art-technical Research, in: A. Hoppe-Harnoncourt, E. Oberthaler, S. Penot, M. Sellink, R. Spronk (eds.), Bruegel. The Hand of the Master. The 450 Anniversary Edition. Essays in Context, Vienna, 52-64. (link)

Upperleft corner of the Metropolitan Museum of Art, Harris
Brisbane Dick Fund, 1932, inv. no. 32.63 woodblock, in a comparison between visualizations with the MSMicroD (color and normal map), as discussed in the reference below.

Watteeuw Lieve 2019: Bruegel’s Drawing of The Dirty Bride (C. 1566). A FINGERPRINT Project Case Study, in: Maarten Bassens; Lieve Watteeuw; Jan Van der Stock; Joris Van Grieken (eds.), Bruegel in Black and White. The Complete Graphic Works, KBR, Brussels and Thames & Hudson, London, 50-57. (link)

For a recent publication in which MA-XRF, standard photographic and multispectral imaging methods have been combined, see:

Watteeuw Lieve, Marina Van Bos, Joris Van Grieken, Maarten Bassens,  Bruno Vandermeulen & Hendrik Hameeuw 2021: View of the Strait of Messina, by Circle of Pieter Bruegel the Elder: Drawing Techniques and Materials examined, in: Curie Christina (ed.) The Bruegel Success Story, Papers Presented at Symposium XXI for the Study of Underdrawing and Technology in Painting, Brussels, 12-14 September 2018, Underdrawing and Technology in Painting, Symposia 21, 465-475. (link)

Launch pixel+ viewer: New dimensions take a deeper look at heritage

press releases in English, Dutch, French

Together with the Art & History Museum and the Royal Library of Belgium (KBR), KU Leuven is launching an online open access application to view heritage objects dynamically and interactively online. This pixel+ viewer allows you to view centuries-old objects in a different light and reveal hidden details.  

Japanese print on paper (© KU Leuven Libraries collections) in the pixel+ viewer

As a result of the Corona crisis, museums and other heritage institutions today have little or no physical access, both in Belgium and abroad. It puts the consultation of objects and the study of our past under strong pressure. In part, we can fall back on digitised objects, notes and old publications, but these only represent part of the information, which means that important details can be overlooked. Fortunately, the sector, in collaboration with engineers, has devised solutions to remedy this.

In the heritage sector, the digitisation of objects has long been the focus of attention and experimentation. For the public, this usually results in an online photo that can be zoomed in or on which the contrast can be adjusted. These are purely colour images, standard digital photographs conceal no extra information. However, different types of image scanners register a lot more characteristics of a surface than just the colour. Being able to visualize this information in a handy online tool therefore offers new possibilities for anyone working with heritage objects. Think, for example, of the KBR drawings by Pieter Bruegel the Elder that were recently examined by KU Leuven. The researchers were able to study the paper down to the fibre using their Portable Light Dome (PLD) scanner. They also got a much better view of the extensive range of techniques used by the old master.

Detail on original Pieter Bruegel the Old drawing from 1557 (KBR: II132816, Luxuria), without colour the imprinted stylus traces of the engraver become visible (© Fingerprint, KBR and KU Leuven).

Software is the key

Over the past 15 years, KU Leuven researchers, together with various partners from the heritage sector, have developed digital techniques that can visualise objects to an unprecedented level of detail: the PLD scanner. “With this method, they illuminate an object from a large number of angles and take photos of it, the so-called ‘single-camera, multi-light recording’, says Hendrik Hameeuw, co-coordinator of the project at KU Leuven. “The way in which this recording is subsequently processed determines which characteristics of the surface, such as relief or texture, the software can show and thus how the user experiences the object”.

New universal file format

 “To be entirely complete, we actually have to look at the file types of these interactive datasets,” says Hameeuw. Most heritage institutions calculate and store these types of images of their heritage with a specific image format, usually RTI/HSH. The software developed in Leuven works with PLD files (ZUN, CUN) that have extra functionalities compared to those RTI/HSH files. Pixel+ now makes this way of calculation available to the whole world, not only by offering it online, but also by introducing a new kind of container file for it: glTF. “Compare it with an ordinary photo on your computer. It will probably be a JPEG or GIF file. But if you want to work with it in Photoshop, the program will turn the same image into a PSD file”. These glTFs are compatible with both the Leuven PLD and the RTI/HSH files. “With this we offer a new universal standard for this kind of images and we also open them immediately via the online pixel+ viewer, a kind of free photoshop for ‘single-camera, multi-light recording’ images”. This allows both RTI/HSH and PLD files to be studied and compared within the same program for the first time.

A new world

Pixel+ extracts a lot of extra information from the available data. The objects, such as old coins, miniatures or paintings, suddenly acquire extra dimensions after hundreds of years, which can be used for research on these objects to gain new insights. Especially in the field of 3D (geometry) and the correct understanding of the reflections of light on an object, the Leuven software is taking major steps forward.

“The technology is interesting for many objects, from clay tablets over coins to paintings or medieval manuscripts,” explains Hameeuw. “The software allows, among other things, the objects to be viewed virtually with different incidence of light, the relief to be mapped at pixel level or a 3D visualisation to be generated”. Frédéric Lemmers of the KBR Digitisation Department joins in: “By even combining it with multi-spectral imaging, researchers recently discovered that the heads of some figures in KBR’s 13th-century Rijmbijbel were painted over at a later date.” At the Art & History Museum, the technology was used to make heavily weathered texts on almost 4,000-year-old Egyptian figurines readable again.

Institutions from all over the world, from the Metropolitan Museum of Art in New York (USA) to the Regionaal Archeologisch Museum a/d Schelde in Avelgem (Belgium), will be able to upload, consult and study their own datasets or files in pixel+. The software converts the information according to various new standards and allows users to access the virtual heritage objects interactively. “This development really is a milestone for the heritage sector”, emphasises Chris Vastenhoud, promoter of the project from the Art & History Museum. “A whole new world will open up for heritage institutions worldwide. They will be able to document and share a lot of additional information in order to communicate about the objects in their collections”.

Pixel+ is available to everyone at with examples of objects from the collections of the Art & History Museum, KBR and KU Leuven.

The online pixel+ viewer with an example of a cuneiform tablet from the collection of the Museum Art & History, Brussels. (© Art & History Museum and KU Leuven).

The project is a collaboration between Art & History Museum, KU Leuven Department of Electrical Engineering, KU Leuven Illuminare, KU Leuven Libraries Digitisation and KBR; and was funded by the Federal Science Policy Office (BELSPO) through the BRAIN-be programme (Pioneer projects).

At the beginning of April 2020, the pixel+ project staff already presented their results during the online (as a result of Corona) SPIE conference. As a result, the paper below was published: 

Vincent Vanweddingen, Hendrik Hameeuw, Bruno Vandermeulen, Chris Vastenhoud, Lieve Watteeuw, Frédéric Lemmers, Athena Van der Perre, Paul Konijn, Luc Van Gool, Marc Proesmans 2020: Pixel+: integrating and standardizing of various interactive pixel-based imagery, in: Peter Schelkens, Tomasz Kozacki (eds.) Optics, Photonics and Digital Technologies for Imaging Applications VI, Proc. of SPIE Vol. 11353, 113530G. (DOI: 10.1117/12.2555685)

read paper – see presentation

Additional examples can be viewed and created at





MS PLD results of FINGERPRINT project in KU Leuven Campuskrant

campuskrant jg 31 nr 1_Page_02_uitsnit

Cartoon by Joris Snaert © on the use of the Portable Light Dome when digitizing a Bruegel drawing (page 2 of Campuskrant 31/1) 

In an interview in the KU Leuven university journal Campuskrant with prof. Lieve Watteeuw the KU Leuven contributions to the FINGERPRINT project have been highlighted in length. The Campus article focuses on the work with the original drawings by Pieter Bruegel the Elder and how the imaging effort by the FINGERPRINT-team have made the difference to better understand the virtuosity of Breugel the artist.  These results will also be presented on the KBR exhibition: The World of Bruegel in Black and White.

PDF of the complete campuskrant edition

campuskrant jg 31 nr 1_Page_08-09

Two page article on the Bruegel research by the KU Leuven in the FINGERPRINT project (©Campuskrant 31/1, pages 9-8) 

Pixel+ project: First results


The PIXEL+ project aims to formulate and engineer methods to bring together existing multi-light reflectance (MLR) imaging methods. That is to make it possible image data-sets (processed or not) from one system can benefit from the processing, viewing and analysis strategies applied by others. Secondly, the project develops a browser-based viewer in which a set of MLR types of data-sets can be consulted with a extended number viewing and analytical solutions.

“Pixel+: Universal web interface for Interactive Pixel Based file formats” is funded via Belspo BRAIN-BE Pioneer  and coordinated via the Federal Scientific Institution: Royal Museums of Art and History, together with the formal partners Royal Library of Belgium, ESAT (KU Leuven) and Illuminare (KU Leuven), informal KU Leuven Libraries.

First results

During 3 conferences (DH Benelux, DH2018 & EuroMed2018), spread over the last couple of months, the project goals and the first results have been launched.

Page1   Screenshot_webpage

Left: DH Benelux at Amsterdam conference abstract
Right: DH2018 at San Francisco conference manage session

Page1    Poster

Left: EuroMed2018 at Nicosia conference paper (Award: Best Short Paper)
Right: EuroMed2018 at Nicosia conference poster

The first major step which has been made comprises the integration of processed RTI data-sets into the PLDviewer environment.

Next steps

  • Fine-tuning of the first integration method (processed RTI into PLDviewer).
  • Assessing the challenges related to the re-processing of the original source files to allow in depth integration of both the RTI and PLD strategies on each other’s data-sets.
  • Launch of a new browser-based viewer in which RTI and PLD data-sets can be consulted and analysed.

New paper and poster presented at the Archiving 2018 conference

At the Archiving 2018 conference (April 18-20, NARA, Washington, IS&T) a new paper and poster was presented: Bridging Multi-light & Multi-Spectral images to study, preserve and disseminate archival documents.


Bruno Vandermeulen, Hendrik Hameeuw, Lieve Watteeuw, Luc Van Gool, Marc Proesmans, Bridging Multi-light & Multi-Spectral images to study, preserve and disseminate archival documents, Society for Imaging Science and Technology, Archiving2018: Final Program and Proceedings pages:64-69


Final Report EES-project

The EES-project collaborated in the joined effort to develop the multi-spectral component of the Portable Light Dome system. Below the final report of the entire project as published via its funding organisation BELSPO (see also their projects webpage):


Luc Delvaux, Hendrik Hameeuw, Athena Van der Perre, Vanessa Boschloos, France Ossieur, Bruno Vandermeulen, Marc Proesmans, Dennis Braekmans 2017: Conservation, IR, UV and 3D-Imaging: The Egyptian Execration Statuettes Project. Final Report, Belgian Science Policy – Brussels, pp 66. (DOI: 10.13140/RG.2.2.10989.28649)

Pieter Bruegel the Elder under the PLDs

In 2019, worldwide attention will be paid to Pieter Bruegel the Elder. It is then exactly 450 years ago that the famous artist
passed away. Therefore, Bruegel will be celebrated in exhibitions all over the world. But, new exhibitions require new research and research techniques. That’s why the Royal Library of Belgium and the KU Leuven joined efforts in the context of a BRAIN-BE project funded by Belspo. FINGERPRINT is an interdisciplinary project in which art historical and artistic research, digital imaging and image processing, conservation and restoration projects and data management are brought together. All these efforts include as well the use of both the White Light Portable Light Dome (WL PLD) and the Multispectral Portable Light Dome (MS PLD). Their datasets are being combined with the output of standard technical photography techniques. The ultimate goal of the FINGERPRINT project is to join all this static and interactive information and develop tools and methods to analyse objectively drawings, prints and engravings of this master and others; to create a platform to examine and understand a historical artifact automatically.

A first introduction article on this new project in which the PLD systems are being applied has been published in the journal Science Connection by the Belgian Science Policy Agency Belpso:

Joris Van Grieken, Lieve Watteeuw, Bruno Vandermeulen, Marc Proesmans & Maarten Bassens 2017:

  • Fingerprint onderzoekt Pieter Bruegel de oude: De start van een interdisciplinaire studie van zijn tekeningen en prenten (Dutch version),
  • Fingerprint, projet de recherche sur Pieter Bruegel l’Ancien: Le lancement d’une étude interdisciplinair de ses dessins et estampes (French version),

in: Science Connection 45, 32-36.


PLD-team of the RMAH @ the Vatican

IMG_0879Veronique Van der Stede (RMAH & ULB); Anne Devillers (RMAH & ULB); Athena Van der Perre (RMAH & KU Leuven); Hendrik Hameeuw (RMAH & KU Leuven); Vanessa Boschloos (UGent & RMAH)

The PLD-team of the Royal Museums of Art and History participated at the Second Vatican Coffin Conference from the 6th till the 9th of June 2017.  In a paper they demonstrated the uses and results of the multispectral PLD system for the study of the pigment and varnish layers on Old Egyptian coffins.

H. Hameeuw, A. Van der Perre & V. Boschloos: #multispectral, #mobile, #interactive: Imaging polychrome surfaces with the MS PLD system.