Refreshing your memory, in the previous blog “Talking about everything visible and invisible (I)” we briefly told you about the digital technologies and techniques used to inspect, document and analyze Cultural Heritage in the visible range (the one that our eyes capture). It is now time to tell you about the complementary technologies and techniques that work in other ranges where our eye does not see (the invisible), allowing us to know about composition, history and conservation needs. Here they are:
X-ray techniques: X-ray radiography and X-ray fluorescence (XRF) imaging are helpful in examining the internal structures and material composition of cultural heritage objects. These methods aid uncover hidden layers and construction details that are vital for restoration and conservation efforts.
Source: rxpatrimonio.com
Infrared (IR) imaging: near-infrared (NIR) reflectography, infrared thermography, and infrared spectroscopy are used to analyse pigments, identify underdrawings or alterations, and study the degradation of materials. This provides a deeper understanding of the original techniques used by the artists and the changes that the objects have undergone over time.
Ultraviolet (UV) imaging: is utilized to highlight the fluorescent properties and surface details of objects. This technique reveals hidden markings, retouching, and other modifications that are not visible under standard lighting conditions, offering insights into previous restoration efforts and the object’s history.
Microscopic analysis: employing optical and electron microscopy allows for the detailed examination of minute features, such as pigments, fibres, and inclusions. Microscopic analysis is crucial in the study of material structures and degradation processes at a microscale level.
Source: «La microscopía en el estudio del biodeterioro y la conservación del patrimonio histórico y cultural». Ana M. García https://oa.upm.es/20369/
Spectroscopic techniques: methods like Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), and X-ray spectroscopy provide detailed information about the molecular and elemental makeup of cultural heritage objects. These techniques are essential for identifying pigments, analysing organic materials, and detecting changes related to aging and degradation.
Chemical analysis techniques: gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS) are used to identify and characterize organic compounds present on cultural heritage objects. These techniques allow understanding the material composition and the degradation processes, definitely aiding in developing appropriate conservation strategies.
Non-Destructive Testing (NDT) techniques: computed tomography (CT) scanning, THz imaging, and ultrasound, are crucial for investigating the internal structure and condition of cultural heritage objects without causing any damage. These techniques reveal hidden features, assess structural integrity, and identify potential defects.
Although X-ray imaging can penetrate deeper and through denser materials, and also generally provides higher resolution images than THz imaging, this last is particularly safe for organic materials as it does not involve ionizing radiation (unlike X-rays, which require strict safety protocols to prevent damage to sensitive historical objects). THz imaging provides excellent material contrast for organic and composite materials, leading to a growing demand due to its effectiveness in non-destructive testing.
THz imaging is scarcely widespread throughout the EU but it is primarily found in technologically advanced research institutions, major museums, and specialized conservation labs. CARTIF is fortunate to have a dual-source THz system (100 GHz and 280 GHz) making it the proper partner in supporting museums and any kind of cultural institutions in art conservation and materials science.
THz imaging by CARTIF to provide information about the composition and layering of a parchment: real gold-leaf is clearly differentiated from other materials, such as adhesives, pigments, or underlying substrates.
Additional multimodal analysis methods should be considered to include a temporal dimension, keeping track of the evolution of features and phenomena over time. It implies the integration of data acquisitions from different visible /non-visible technologies into complex data structures that provide new analysis opportunities for scientists, conservators and curators. This requires advanced data processing and visualization tools that act as virtual environments for precise exploration, allowing to fully explore the always complex cultural heritage objects.
Collaborative platforms are essential for sharing and integrating digitized visible and non-visible data in this context, facilitating global cooperation among researchers, conservators and curators and also enhancing the collective understanding and preservation of cultural heritage.
The European Collaborative Cloud for Cultural Heritage (ECCCH), created in 2023 and aimed to create innovative tools for digitizing cultural heritage objects, is a trending topic in the UE applied research to ensure the sustainable and affordable conservation of our historical legacy.
For sure digitising cultural heritageinvolves a wide variety of technologies and techniques, some of which serve to analyse visible issues (those what we ‘detect’ with our eyes), and others serve to discover and analyse invisible issues (those what we are not able to see). Have you ever wondered what those techniques are? Keep reading as we begin in this episode with the visible ones. Don’t be impatient, next time we will explain those used for the invisible.
Digitising the visible characteristics of cultural heritage objects requires at least this range of innovative tools and methods:
High res-3D scanning: to capture the shape, texture and geometry. Techniques such as laser scanning, structured light scanning, Structure from motion (SfM – by means of image sequences) or Neural Radiance Fields (NERF – adding IA to image sequences) are employed to create detailed 3D.
Advanced imaging methods: this can include techniques such as multispectral images (normally between 3 and 20 spectral bands not necessarily contiguous to each other); hyperspectral images (formed by a greater number of bands but always contiguous); or reflectance transformation imaging (RTI), which easily reveal details, enhance colour accuracy, and provide material analysis.
Virtual Reality (VR) and Augmented Reality (AR): to enable immersive experiences and interactive visualisation of cultural heritage objects. They allow users to explore digitised objects in virtual environments, providing a more engaging and educational experience.
Metadata and semantic annotation: to ensure proper organisation and retrieval of digitised cultural heritage objects. These tools enable the description, classification, and linking of objects to related information, such as historical context, artist information, or cultural significance.
Robust data storage and management solutions: As the volume of digitised cultural heritage objects is hugely growing, cloud-based platforms and digital repositories are required to provide scalable and secure storage for the vast amount of data generated through digitisation efforts.
Collaborative Platforms: to ease collaboration among multiple institutions and experts, facilitate sharing, exchange, and collaboration among stakeholders, enabling seamless access to digitised cultural heritage data.
We know how to do all these things at CARTIF. Do you dare to ask us?
Decarbonization is the “trending topic” of terms related to sustainability, energy and the environment. It is the process of reducing the amount of carbon dioxide (CO2) released into the atmosphere. Decarbonization means reducing climate change and dependence on fossil fuels, which are precisely those that emit CO2 when burned (clear examples are fuel-oil and coal). Decarbonization implies the use of cleaner energy sources, but also the adoption of technologies and methods to protect the environment and to reduce these emissions (the so-called “carbon footprint”).
However, what does this have to do with Cultural Heritage? Well, you will be surprised for sure, but it turns out that Heritage contribuyes many important things to decarbonization: the preservation of historical buildings, the reuse of spaces, the promotion of sustainable mobility, the promotion of cultural tourism and technological innovation in the assessment and the conservation of historical assets. In other words, it turns out that offers an environmentally friendly approach to urban planning and rural development.
If we go into a little more detail, you will see that Cultural Heritage can play a significant role in decarbonization and the fight against climate change. Here we provide you five ways to do so, but I´m quite sure your are able to think of some more (please tell us):
Technological innovation applied to conservation1 of historic buildings (where CARTIF has a lot to say): here the sensitivity required by historic buildings implies the development of specific techniques and technologies, which have broader applications in reducing carbon emissions in other fields of construction and environmental management. The digitally based technical inspection, the preventive conservation and the intervention involving H-BIM avoid both ruin and/or demolition, as well as new alternative constructions, which significantly reduces the material and energy resources to be used for these purposes. Furthermore, and this is worthy of remark, the old buildings were designed and built up with techniques and materials that are inherently sustainable, taking advantage of aspects that we are “rediscovering” right now such as orientation, natural ventilation and the use of native materials.
Reuse of spaces: Historical sites and buildings can be suitable adapted for new uses and transformed into living or working spaces with a level of comfort appropriate to the 21st century, which in the medium-long term saves resources compared to the construction of new substitute structures. This reuse contributes to greater energy efficiency and the reduction of carbon emissions.
Adaptation and transcription of ancient professional techniques: historic places are examples of how antique societies adapted to environmental challenges (which have always existed) and how lessons learned in the past can be adopted today through proper understanding and technological shift of traditional techniques and uses (both materials and methods).
Promotion of sustainable mobility: The preservation of historic centres in cities increasingly promotes sustainable mobility. In fact, they were desgined to move on foot, on horseback or in wagons and carriages. Therefore, they absolutely favour pedestrian accesibility and the use of public transport instead of private vehicles. This reduces dependence on fossil fuels and decreases greenhouse gas emissions.
Development of sustainable cultural tourism: it is more than proven that sustainable cultural tourism can play an important role in the local economy and even in the region, encouraging more environmentally friendly practices such as waste management, conservation of biodiversity and the promotion of quality agri-food and crafts.
But, does Cultural Heritage really do that much? Obviously yes. Indeed, a lot. In line with the priorities of the European Green Deal and the EU´s climate ambition for 2030 and 2050, the European Cultural Heritage Green Paper emerged in 2021, where indeed it is already considered a driver of decarbonization and mirror upon which citizens see themselves as key actors in the actions needed on this regard.
Historic building and decarbonization is a bionmial over which the Cultural Heritage & Regeneration Committee of the European Construction Technology Platform has been working for years (CARTIF takes part of the Executive Board). Its latest strategic research agenda for the period 2021-2027, promptly refers to this. And it is an issue that has been deepen into recent plenary assemblies. It is no wonder when 24% of the residential buildings in Europe date back to before 1945, nearly half of them have historical value, and of this latter, 73% are located in cities, which is precisely where the alrgest carbon footprint is made.
From now on, will you see Heritage with an additional view further than cultural, religious and tourist ones? Another thing for you to know.
1 In line with UNESCO and ICOMOS usage related to tangible heritage, conservation is considered as the umbrella term to cover a range of preservation, conservation, restoration, (re)use, interpretation and management activities.
A wood lamp emits ultraviolet (UV) light and is a diagnostic tool used in dermatology to determine whether a person has a fungal or bacterial pathology on the sking or scalp. If so, the area illuminated by the wood lamp will fluoresce, becoming apparent in different colours associated with different pathologies. Perhaps you have ever undergone this test. The doctor will have told you to close your eyes to protect your vision and the light in the room where you are he will have turned off to highlight the fluorescence. Among other possibilities, if it turned out light blue means that you have normal and healthy sking; yellow is oily skin with acne; brown is for pigmentation and blackheads; and if white spots appear, drink more water, because you have dehydrated skin.
But surely you had not stopped to think that his technique is also applicable to diagnose similar pathologies in movable cultural heritage assets made of organic materials, for example wood or resin sculptures, or paintings covered with varnishes madre from three resins. The passing of the years, inadequate conservation conditions and dirt are defining aspects in the appearance of fungi or the yellowing of varnishes, so that if sculptures or paintings are illuminated with a wood lamp, we can clearly distinguish fungal conditions, and the extent of dirt (even where they are not yet perceptible to the naked eye), or if a painting has been touched up because the yellowing of old varnishes turns fluorescent.
Heart of Jesus inspected with wood lamp
In the ITEHISproject a wood lamp that emitting light around 365nm (UV) and producing fluorescence around 500nm (perceptible by the human eye) has been used to inspect a statue of the Heart of Jesus from the late 19th century, validating the fungal infection (especially mold) and making evident its true extent.
A wood lamp thus becomes an absolutely effective, eay-to-use, non-invasive and economically admissible mean, even for a person like you and me, to help clean and restore our heritage. A true example of a “low-cost” technique to keep it there. But this does not end here, because further R&D is required to associate new colours with new pathologies in a moment where climate change and human globalization bring “bugs” that do not correspond to the latitudes where they currently appear. But don´t worry about that, CARTIF is already taking care of it.
Cultural heritage, in the broad sense, is the legacy received from our ancestors, which becomes the testimony of their worldview, their ways of life and their way of being, having to be passed down to future generations. Knowing the cultural heritage is to know the identity of a specific society and let me dare say that, without doubt, it even helps us to discover ourselves.
When we are traveling to a certain place to “pick up” that knowledge, but being far away from stereotypes and trivializations, we are doing cultural tourism. Despite the fact that this type of tourism is sometimes controversial (fundamentally due to how resources are managed), it is unquestionable that it has nothing to do with sun and beach tourism. Even though Spain is the second country in the world for highest quantity (and quality) of cultural (and even natural) heritage, it surprisingly continues to present and sell ‘sun and beach’ tourism as almost exclusive. Cultural tourism represents a great opportunity for local development, decisively contributing to conserving and making heritage sustainable, since it has already been proven that generates resources and employment for the community. But for this to happen, it must be oriented not only for the benefit of cultural heritage in itself, but also for the people who inhabit the place where it is located. Only if the inhabitants are really an active component in tourism development, can the spark arise between heritage and cultural tourism, and then it will end up being a well-matched marriage beyond convenience.
The fact is that since the 1970s, when UNESCO launched the Convention on World Cultural and Natural Heritage, together with proposals to conserve and promote it, cultural tourism has experienced huge growth throughout the world, but especially in Europe, where it became really important since the 1980s. In fact, currently there are 1121 declared World Heritage Sites; the majority of them spread around three countries, two of which are European: China (55), Italy (55), and Spain (48).
Europe is a key cultural tourism destination thanks to an incomparable cultural heritage that includes museums, theatres, archaeological sites, historical cities, industrial sites as well as music and gastronomy. According to CARTIF’s analysis in 2021 for theTExTOUR project, it is estimated that cultural tourism accounts for 40%of all European tourism. This is generating 5 million direct jobs and contributing 143 billion Euros per year to the EU economy. Indeed the EU promotes a balanced approach between the needs to boost growth on one side, and the preservation of artefacts, historical sites, and local traditions on the other.
Pandemics apart, it is estimated that cultural tourism will remain one of the key markets in Europe. Interestingly, cultural tourists spend 38% more per day and stay 22% longer than other tourists. Germany is the largest European source market in terms of market size, followed by the United Kingdom, Italy, France, the Netherlands and Spain. Trends show cultural tourism is slowly changing into creative tourism. With it, tourists actively participate in cultural learning experiences, getting in touch with local people and culture.
Cultural tourism originally was primarily driven by the interest of the baby boom generation (born late 1950s – mid 1970s) to visit major cultural sites and attractions, such as museums and monuments, often travelling in groups. The generations after them: generation Y (millennials: born 1980–1995) and generation Z (centennials: born 1995 – 2010), drive the demand for more authentic, unique, small-scale and personal experiences, plus the demand for popular and everyday culture. For them it is more important ‘to be’ somewhere, rather than ‘to go’ somewhere. These generations prefer to travel on their own, thus flat rental platforms and personally-driven services at local level are growing and growing.
Of course technology has made a substantial change in the habits of travellers. The recent publication of five new standards by the Spanish Standardization Committee (UNE) contributes to providing solutions to the challenges that destinations as well as the companies and agents that operate in them must address through a digital and sustainable model that definitely fits like a glove to the cultural tourism. This model strongly needs to be equal in technological and social development to the digitization of cultural heritage, which is the great pending issue, but CARTIF is ready to help. Do you need us?
