Designing Coloured Experiences

To be able to develop appropriate User Experiences and applications for coloured collections, we have started from the analysis of user’s needs and requirements, adopting a specific design approach known as “PACT” framework [1]. PACT stands for People Activity Context Technology, and it is a way to enquire and let emerge relevant elements to be used in the development of ideas and in the creation of a design briefs. To better adopt this approach, we have developed a question-oriented support for PACT. Questions in fact help to focus and to find answers to common problems within the CH domain. Examples of such questions are reported below in Table 1.

In Volume 2 we describe the design tools, specifically created to support the PACT framework and included in the PERCEIVE design toolbox.

A second approach that we have adopted is users’ behaviours exploration designing specific Cultural Probe Kits (CPK). As already described in Chaps. 3 and 4, Probes were originally developed as a means for designers to detect useful information, ideas, and opinions in specific contexts and in a non-intrusive way [2]. Cultural probes typically are a mix of objects included in a physical box that is given to a number of potential stakeholders for a certain amount of time. The objects are hybrid, therefore they might include fully digital items and other tangible items. They are carefully designed to “provoke inspirational responses” [3]. For example, Gaver’s experiment included a map, postcards, disposable camera, and booklets. Probes do no specifically aim at gathering requirements, rather at confronting and providing inspiration to the designers. Moreover, Hulkko [4] referred to probes as stories or fragments of understanding: they are seen as means to engage with the lives of others. Following this approach, specific Cultural Probe Kits have been successfully produced for the understanding of users’ behaviours referred to the concepts of caring (Chap. 3), of authenticity (Chap. 4) [5] and of social cohesion (Chap. 5) [6]. The result of this work has been included in a project report [7]. Furthermore, in Chap. 5.2 we have reported the results of another exploration carried out on “curiosity and interest triggers” as elements to be considered in the definition of the needs and requirements. The list of the templates are available in Zenodo:

During the first iteration (July-October 2023) we have collected internal requests for specific questions to be submitted to the stakeholders, in line with the scenarios and expected outcomes of the project; we have then designed 5 questionnaires, oriented to the 5 types of stakeholders (Scientists/Conservators, Museum professionals, Educators, General Public and SMEs), meant to be submitted to a limited and representative potential users (10 for each type), to test the questionnaires and their efficacy (in this phase we have used Google forms for a productive collaborative development); we have then submitted the 5 questionnaires to 10 stakeholders, selected considering their relevance and representative role, introduced by an explanation on the perceive project and its goals; we have analysed the answers and started to identify the needs and requirements for the development of tools, services and prototypes dedicated to the analysis, preservation and communication of coloured collections. In the second iteration (January-June 2024) we have modified the questionnaire including the findings from the first iteration and added more specific questions, deleting questions not understood or needed; we have analysed alternative survey platforms, compliant with GDPR; collected data have been secured stored and analysed; aggregated data were at this point sent to the developers and designers of the applications. Since the second iteration is still on-going, we report here the statistics of the first iteration only. We have collected data from 11 museum professionals (working in institutions such as the MANN museum Italy; Museum of the Imperial Fora Italy; Victoria and Albert Museum London; Acropolis Museum Greece; Museum of art and design Italy; Gallerie Uffizi Italy; Sistema Museale di Ateneo University of Bologna Italy; Vatican Museums); 25 scientists involved in studies in the five reference scenarios (Chap. 6); 6 creative industries engaged in fields connected to virtual museums, digital exhibitions and digital art; 15 citizens (adults and young adults); 10 educators teaching mainly at the university, but also in high schools and primary schools.

The final objective of the PERCEIVE project is to develop new ways to perceive, preserve, curate, exhibit, understand and access coloured Cultural Heritage collections and Digital Artworks. The starting point for discussion is the analysis of the main workflows used by the professionals and scientists involved in these activities.

Studying, preserving and communicating colour and coloured collections require, in fact, different activities, some iteratively carried out, others in parallel, others in a temporal sequence. 9 types of activities have been identified for the purpose of the project and for their description, an internal focus group with the PERCEIVE experts of each Scenario has been created. Specific questions have been included in the five above-mentioned questionnaires, to validate the relevance of the activities beyond the project’s development.

The identified sequence of activities common to the five PERCEIVE scenarios is as follows:

In the following paragraphs, these activities are described in detail, together with their main issues, the type of involvement of different professionals, the complexity of the work, the impact on the community, required input data and the produced outputs.

Scientific analyses covering a whole range of techniques and analytical approaches (from non-invasive punctual analyses as XRF, Reflectance spectroscopy, Raman spectroscopy, or mapping/imaging methods, as Hyperspectral/multispectral analyses, X-ray radiograph, MA-XRF imaging, 3D Hirox mapping and acquisition to micro-destructive tools needing small samples from the object – microFTIR, microRaman, XRD, GC-MS, MALDI-MS or MFT etc.) are the core of the first step of material characterization and colour change detection when speaking about colourful art-objects that can be subject to change [13, 14]. This range of techniques and methods can give compositional information together with mapping the distribution of coloured materials on the surface and in the structure of the art-object, especially for those multilayered structures we often meet in paintings or photographs [15]. Based on this compositional and stratigraphic information further studies around the possible phenomena of colour change can be performed, involving more specific tools as hyperspectral/multispectral and colourimetric techniques (colourimetry CIEL*a*b*, microfaedometry, MFT).

The colour change often is not easy to detect when it happens on small areas, but when affects the whole object or a material that is relevant and visible on the whole object’s surface it can impact the readability and material integrity of it. Thus, in the scientific investigation of such phenomena it is important to have a complementary and multiscale approach, where the change is mapped and characterised from a macro up to nano-level, when possible. The type of sample or surface/material that presents the colour change is also relevant for the choice of the best analytical approach and for complementing bulk analysis with surface investigation.

Furthermore, in addition to the real object and eventually samples that can undergo analysis for a better understanding of the change phenomena, laboratory research on model samples might be required to shed light on aspects of the chemical and physical processes that are involved. These model samples (known also as mock-ups) will be subject to similar analyses as the real samples or objects in order to compare compositional and other type of features. These models have the advantage that they can be destroyed during the analytical investigation. One example of how mock-ups can complement the analyses on real samples and give important clues on the colour change phenomena (in this case is the fading of cadmium yellow) is described by Letizia Monico [16], (Fig. 1).

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The main issues come from the limitations of the analytical tools themselves (e.g. whole surface vs. point analyses; dimension of the areas to be analyzed; multilayered structures difficult to access/analyze if the tools do not provide enough depth of penetration for the radiation to map the overlapping materials/layers etc.) but also from the immediate availability of these tools in the museum environments. Not many museums in the world can afford to have a Scientific Department with such analytical tools. When a Conservation/Heritage scientist is not available sometimes conservators can take over the task of doing some simple analyses (pXRF, MFT or FTIR) or they can ask collaboration to other laboratories where more techniques and resources are available. Some might be accessible through photographic laboratories that are used to document artworks on periodic base for different purposes (conservation state assessment, loans, exhibitions or conservation projects, research projects) but in these cases it is difficult to establish a monitoring schedule for this type of documentation or detection.

Another problem of a nature more specifically linked to the management of collections in museums is the possibility of access to the artwork itself; in museums, not all objects are often on display: those kept in warehouses, for example, require precautions and in most cases, if dealing with marble statuary, preventive conservation is required before applying multispectral diagnostics. In the application of multispectral/hyperspectral investigations, it is necessary to know in detail all the conservation and restoration interventions that the object has undergone over time, and when possible, the factual history from the moment of discovery to its permanence in private collections, up to its arrival at the place of current exhibition.

The complexity of the analytical approach sometimes might require external funding for specific investigations (such as access to MOLAB and FIXLAB facilities within E-RIHS platform¹), whose results are extremely valuable for conservators and also scholars in the field of museum research who need a more detailed and scientific background on the type of colouring materials used, their behaviour and ageing in time, their techniques of application, possible interactions with environmental factors as light, relative humidity, temperature, polluting agents etc.

An additional issue is represented by the availability of repositories, archives and databases of scientific data. These are not always openly accessible or are difficult to be related with other databases online (when comparison of results is needed for example). Archival data are often very complex to interpret because they use outdated language and words that in some cases have fallen into disuse. Hopefully, in most cases the results are easily available (and for free) only if published in Open Access platforms or journals. Regarding the use of images and data from previous investigations on a work of art, many museums have internal protocols that protect the dissemination of the material and sometimes it is not possible to access, except for mere consultation purposes, at previous research. Once all the data necessary to frame the work from the point of view of colour research has been obtained, it is necessary to arrange for its storage: this operation is also not free from problems since, for example, many museums do not have digital repositories that can host a large amount of data.

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Imaging diagnostics tools offer different applications according to the type of coloured object investigated and their material structure and shape. 2d objects as canvas or cardboard paintings, graphic art on paper (drawing, prints), negatives/positives of old photographs have less depth and tridimensionality but often the surface presents its own 3D profile and can be investigated with three dimensional tools (as video-microscope, OCT tomography or Hirox 3D digital microscope) for topographic, direct and raking light, real colours observations and 2d/3d scans at different magnifications and degrees of resolution. Often the photographic documentation can offer a certain amount of details regarding the condition of the art-object and possible degradation and deterioration patterns, but a more in-depth investigation with 3D equipment (as Hirox 3D microscope) can lead to a multiscale approach in the investigation of surface and multilayered structures and also recording of profilometric data [17] Fig. 3 and Fig. 4 show the Scream (1910?) investigated with different photographic techniques before and after the theft (2004–2006 is the period when the Scream was lost).

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Other techniques of imaging that also offer topographic information (3D digital microscopy, profilometry, OCT scans) are a good complement of a normal or raking light photography to document the surface patterns and colours of a painting and also to showcase the difference between several areas with colour changes. In the case of The Scream (1910?) 3D microscopy technology allowed for visualizing at different magnifications (30x, 90x) areas with fading phenomenon (Fig. 5) to be further used for 3D prints as demonstrators in Perceive.

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For 3D objects (textile dresses or sculptures in stone), photogrammetry, laser scanners and other 3D acquisition techniques can be used to reproduce their shape, colour and texture and also evaluate eventual degradation.

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In many cases the main difficulty is connected with the access to the artwork if the scientific laboratories are not part of the museums. Moreover, professionals have to consider objects characteristics, as they might be too fragile, too big or too valuable to be easily transported to external laboratories. For this situation often mobile facilities (e.g. MOLAB - IPERION HS platform²) can be accessed according to a specific call for applications subject to evaluation.

Other issues are related with the development of the acquisition equipment and its performance (including the upgrades of software). For photographic techniques for example the illumination conditions and also the use of metric references or colour checker for the photographs are important parameters to take into account for future documentation and reproducibility of colour features in the recorded objects. A consistent and well-established protocol for visual (and analytical) documentation of these objects would be ideal for any institution owning an art-object collection subject to change and degradation.

The colour change phenomena in art-objects can be studied and monitored with different tools based on imaging acquisition principles and colourimetric measurements such as MFT (microfadometer testing), CIEL*a*b* colourimetry, Hyperspectral imaging etc. These tools are useful to monitor the degree of colour change and predict the decay rate or value of allowable lux-hour (lux-h) exposure for a sensitive surface or material. Their limitations reside in the fact that for most of them the colourimetric data is based on punctual measurements not on maps. It is always imperative that these kinds of tools are supported with data from analytical characterization of materials to establish the categories of sensitivity, according to generally accepted standards. Once the categories of sensitivity are established among the coloured objects (paintings, prints, drawings, watercolours, dresses, photographs) of a collection, a policy for illumination and exhibition can be created in a museum.

A much more complex matter is that which concerns the monitoring of three-dimensional works, specifically stone ones, since the traces of colour, if they have not previously been documented, are to all intents and purposes non-existent: for this reason, for this specific typology of object, an investigation protocol should be established enabling working in parallel with standardized diagnostics (state of conservation following NORMAL Recommendations for example): where the colour is not found the risk is that of its definitive disappearance or cancellation, due for example to incorrect handling/restoration/conservation activities. A further aspect to evaluate is the impact of environmental pollution, chemical, physical and biological: in both cases the particulate dispersed in the air can attack stone surfaces and alter or destroy what remains of the presence of pigments and their binders. Colour mapping and its state of conservation should be the basis of the choice of whether or not to exhibit each work. There are cases, such as the Venus in Bikini from the MANN in Naples whose continuous loans often due to exhibitions all over the world, represents a very serious risk factor in the conservation of the gilding (Fig. 7).

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The colour change monitoring can be performed using a parameter that is Just Noticeable Change (JNC). JNC value perceptible with naked eye shows when a colour has changed. By combining the Blue Wool standards (the responsiveness of material to light) with JNC values (for example for fading of a colour it would be JNF) we can estimate the amount of light a collection item of a particular material can be exposed to light before it fades in a visible way (reference from international standards BS1006 and ISO R105 -Table 2). With a value of 10JNF an item might not be exposed longer because of the amount of fading or discolouration that have occurred. A thumb rule that can apply to these calculations for establishing the period and lux-h exposure for sensitive objects is based on the reciprocity principle of light exposure by varying the intensity/dose of illumination, allowing a longer exposure in an exhibition at low lux-h values being presumably equivalent to a shorter exhibition (in h) with higher illumination intensity (lux) value. When the object is sent on loans and repeatedly exposed, the effect of light is cumulative, so the average illumination conditions have to be correlated to the hours of previous exposure to certain level of lux-h.

As example of such calculations and exhibition policy is the way the different versions of The Scream painting have been evaluated in a MFT campaign in 2019 [23]. We know by now that there are 2 versions in MUNCH museum collection that are mostly sensitive to light and humidity (for Cd yellow paints – one of the most sensitive material in the tempera and oil version): The Scream (1910?) is in category BW2/BW3, while the hand-coloured print (1895) is in category of higher sensitivity, BW1 (Fig. 8). That means that JNF (Just Noticeable Change) can occur in 50 y if the Scream (1910?) is exposed at 1.000.000 lx-h/year (between 66,7 to 200 days) or in 100 years if the value is 15.000 luxh/year, while for the other version this change can happen in 20 days if the exposure is done at 300.000 lx-h/year (for both, the maximum level of exposure is 25 lx for 1 h).

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Based on these estimates, the present exhibition set-up (Fig. 9) displays 3 versions of the Scream (not the hand-coloured print but another black and white version, and as there are many copies they can be substituted every 5 months), each exposed for 30 min, in an alternate mode, along a full day of museum opening hours, at 25 lx/h. The level of illumination is thus reduced and the visitors can appreciate each version at a time, never all 3 together, in a space with black walls. Each version is housed in a showcase with automatic doors, that only open when the time to exhibit a version has come. This kind of set-up (Fig. 9) represents a temporary exhibition and has its own limitations regarding the fruition of the whole object and of its details. The information provided in the current set-up does not explain enough the reason behind this choice and the low light levels. A virtual content or augmented reality application able to display all the versions of the Scream (even those that will never be on display) at the same time as the real object with options to also showcase the science behind the colour change using images would very well complement the understanding and appreciation of the full value of these very precious and unique objects.

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A museum is due to carefully and permanently monitor the condition of sensitive items in its collection. An illumination policy can be implemented after establishing a plan for continuous monitoring and mitigation of negative effects of prolonged exposure to light and other environmental factors that can induce colour change. Drafting this policy requires dialogue and common decision making between collection managers, conservation and scientific staff and also exhibition/light designers.

The main output of such a policy is to ensure that the objects are preserved in a stable condition for as long as possible before a JNC occurs. Few online applications are available for some type of objects and materials from museum or conservation institute, but there is no virtual application that shows visually how the change can occur and what the best course of action would be to mitigate the effect of light exposure.

A crucial activity includes the study of the historical and artistic context to better understand how artists have produced their works, analysing the various materials, purposes and contexts. As an example of such activity we report below the approach followed by the scientists studying lost polychromy on ancient statues.

This branch of studies was born in the 19^th century and had its first peak in 1830 thus starting a debate that has not stopped to this day: the prevailing topic, however, contrary to what one might think, did not concern artistic artefacts such as sculptures but rather architecture, therefore the main actors in these interesting debates were architects and not archaeologists, thus giving a very technical imprint to this aspect of art. Analytical field research on the polychromy of Classical marble architecture saw a new beginning in the 1980s with the German research on the temple of Aphaia at Aegina, a building that had been a focus of polychromy research since the early 19th century. Recently, in the last 40 years, the debate has greatly shifted to the artistic and statuary field, launching a second line of research of extreme historical and documentary interest. Although in the beginning there was more discussion on the artistic and aesthetic aspect, the scientific research of materials has managed to carve out a completely different space for itself over time, becoming today the entire fulcrum of the research, the basis on which to hook the documentary and historical part of the process of knowledge. Despite this background, the literary production of the 19th-century full of coloured documentations and excavation data is crucial to deepen to delve into the conservation history of the object and understand how the conservation of colour has changed over time. What do we know about colouring? What can be assumed from archaeological research? For sure we know that the final effect of colouring a surface could be achieved by exploiting the natural colour and texture of a construction material, or by applying paint but more generally the two methods were combined. To reach the ideal final result, there was a specific selection of rocks to be used (or avoided): the preference was quite mandatory since the chosen stone should have some specific characteristics such as being polishable and uniform. There was a basic pigment palette, which was universally applied in both Greek and Etrusco-Roman architecture and also to sculpture, included minerals (iron oxides of local origin and in shades of red, yellow, green, and brown), artificially produced pigments (Egyptian blue, lead white, calcium carbonate white, orpiment), and organic colours (carbon black). More precious and brighter pigments (green malachite, blue azurite, red cinnabar) were usually applied on protected surfaces and architectural sculpture [12]. Not knowing the basics of polychromy standards, with all its subsequent nuances, means setting up the entire research incorrectly: this is why, together with scientific research and analyses of the materials, it is necessary to know in depth the entire history of the object, including the more specifically iconographic aspect. Having a clear iconographic framework of reference is a solid and correct basis for setting up the search for traces of colour in statuary which, unlike painting or frescoes, is sometimes not visible to the naked eye but whose evidence can only be mappable by a specific diagnostic instrumentation.

In this phase, we digitally reconstruct the museum item or artwork as it is today with its shape, material and colour, trying to create a digital twin of it. We use a reality-based acquisition and reality-based modelling approach adopting photogrammetric and laser scanner approaches, often combined to acquire the geometry and the RGB colour characteristics. Data post processing require an optimization of data, in line with the chose visualization tools. Moreover, the final 3d model is mapped with RGB texture and with the diagnostic analysis previously acquired, especially the imaging (as UV and VIL).uun

With this activity, we create a digital simulation of the item (or part of it), using data acquired in the previous steps, to obtain a new version in a different time frame (digital restauration with colour reconstruction, digital reconstruction with the potential original aspect the item might have had, digital simulation of how the item could evolve in the future). This activity requires to use the reality-based models obtained with Activity 5 and integrate all available sources of information (direct, indirect, comparison with similar cases) to produce a new simulation model. The work of 2d and 3d artists is often required. Colour itself was a medium in ancient times, that’s the reason why it is mandatory to recover it. Its relevance is evident for the meaning of a work, as well as the social function of the colour code. The study of colour should embrace other disciplines such as anthropology, linguistics and history without subordinating form to meaning. Colour in ancient times was an extraordinary resource to classify and evaluate society: colours had functions and meanings, were not only mere decorations of stones: they highlighted roles performed in the realms of communication and information. Being able through digital modelling, for example, to access the reconstruction of the image and consequently to its contents and meaning makes available to scholars, as well as the public, a wealth of knowledge that is not guaranteed today. Allowing people to correctly approach the meaning of works of art is of primary importance for the correct diffusion of culture by the relevant bodies; many attempts at physical reconstruction of 1:1 copies of some significant works (such as the Riace Bronzes) have been experimented but the limit between what we can actually deduce through scientific research and what we decide to offer to the public is a delicate border. For this reason, the digital reconstruction/restoration is the only chance we can adopt to correctly convey both the results of scientific, historical-archaeological and finally artistic research. Only by combining these three areas of study is it possible to correctly reconstruct the story of the object and only through the exploration of the potential that the digital world offers we can redefine the concept of culture and sense of care.

Every coloured material in the structure of an art-object requires special attention when subject to fading or darkening due to its composition or behaviour to environmental factors. Conservators are the key professionals in a museum that deal with the intimate understanding of these materials and their ageing as they are often called to identify the cause of degradation and propose measures for mitigating the risk of further change or decay or intervene to re-establish the integrity and chromatic wholeness of the object if materials have been lost creating lacunae that disturb the visual appreciation of the object. They eventually work in close contact with scientists and exhibition designers to establish the best conditions of access and usage in different contexts where exposure to light and other environmental parameters needs monitoring and control. Preventive conservation policy [24] is made to establish safe limits for such exposure and calculate the extension and impact of the risk factors (light, humidity, pollution, vibration, pests, vandalism etc.). A magnitude of the risk has a specific calculation formula that implies knowing the following values: object importance, its loss in value, probability of risk occurrence for 100 years and extent of the risk. This will also impact on the display experience, especially for highly fragile and valuable objects, as in the case of The Scream.

Virtual restoration of objects (including the colour reconstruction for areas with change and loss of colour) in exhibition setting is not always possible due to limited space and also restricted exposure levels. In addition, sometimes the accuracy of such a simulation or rejuvenation can be difficult to attain if no original resources or references are available. Nevertheless, the colour science progress using software processing can overcome this challenge and create colourimetric references from scientific results produced with spectral or microfaedometric equipment [25‐27].

Virtual or augmented reality applications can be a useful tool to associate with other services or applications for creating educational contents or even prototypes for enhancing the sense of care and authenticity about these objects. The colour and its fading (or darkening) can be protagonists of a unique story to tell the specialised or more general public using images and videos or interactive contents around the creation of the art-object, its fragility and meaning as a material item but also as a representation of emotions generated by the colour perception and its individual or collective interpretation. The colour becomes thus a vehicle of knowledge and experience of the materiality and the fragile impermanence of artistic expression. The colour itself is a descriptive (abstract or realistic) mean, a tool and a process and its understanding can engage all senses, not only the sight. A colour is seen, touched, heard and felt in all its multidimensionality and the experience behind all these ways of bodily engagement (known as embodiment) can be inspired and guided by a science-based approach.

In the communication activities, we design and develop interactive and not interactive applications (media in general) to involve and communicate the museums coloured collections and artworks to the public, but also to visually and collaboratively share results with experts. The applications could vary in accordance with the general framework and type of experience (virtual, augmented, mixed, hybrid), and in accordance with specific categories such as: the type of content and the institutional/scientific/audience goals; with the Visualization and Interaction technology, with the type of access and distribution (remote or on site), with the communication style (descriptive vs dramatic), with the level of immersion [28]. Moreover, the user-cantered approach widely adopted in design has recently further evolved into a more concept-oriented approach. This mean the main goal of such applications could be set as to make the users reaching specific cognitive and emotional objectives. PERCEIVE has identified 3 of these objectives:

This activity starts with the co-design phase, that involve all involved professionals, together with the users. It might use design tools such as the Visitor Card box⁴ or other similar tools produced by the GIFT project⁵. It then proceeds with the creation of a User Experience, supported by diagrams, storyboards and scenarios. In parallel one or more narratives and storylines are created; it specifies the User Interfaces and Interaction modalities; It define the framework for its development. The final phase is that of the development of a prototype that is then tested and with the creation of the final product.

Nowadays, the 3d documentation and reconstruction of ancient artefacts or historical sites are a common practice in the cultural heritage field [29]. The 3d models are not only visualizing tools but also a way to communicate the work methodology of researchers and experts in the field. Since digital reconstructions always come with a certain degree of interpretation, it is more correct to talk about a “reconstructive hypothesis” [30] which therefore needs to be visualised together with transparent data. Transparency is the property of materials that allows us to see things through them. Seemingly, methodological transparency is the level at which the user can access and visualise the data history of a specific object, showing what lies behind it. Transparency in research methodology refers to the clear and comprehensive presentation of the research design, data collection, and analysis processes. This notion is essential, since it ensures the validity and reliability of and fosters trust in the research findings; it determines not only how much can be recovered, but helps to understand the data, therefore allowing experts and scholars to retrace critical decisions and test conclusions on colleagues’ work of and on their own research [31]. The London Charter defines Intellectual transparency as: «The provision of information, presented in any medium or format, to allow users to understand the nature and scope of “knowledge claim” made by a computer-based visualization outcome». What Transparency can describe to researchers and scholars is metadata and paradata. Metadata is useful to describe, manage, preserve, and use the model’s data, its content, and its context. On the other hand, paradata refers to the actual use of data: paradata will indicate for example how people use a specific book and its source, while metadata will be the book’s title, author, etc. While most of the time metadata and paradata in museums are not transparent for the general public, the European project PERCEIVE (www.perceive-horizon.eu), dedicated to the study and reconstruction of coloured museum collections, is engaged in unveiling the results to everybody.

Digital models are not only an “aesthetic” simulation of reality, but they are interactive, manipulable, interrogable, and navigable models which allow new ways of visualisation and access to data and information. Normally, the viewer is presented with the work without commentary about other possible poses in which the object might be realised or reconstructed. Transparency is desirable and entails the presentation of a real-world basis for a virtual reconstruction. One of the main objectives of Kensek [32] is to reply to the question how to use virtual reconstructions in order to enhance scholarship and education (whether of archaeologists, architects, graduate students, third-graders, or tourists) rather than distracting from it. Their work consists in a methodology for making ambiguity, quality of the evidence, and alternative reconstructions dynamically transparent to a user. [34] present a methodological approach to display data-processing which aims to validate 3d modelling practice and to facilitate the exchange of information and collaboration. In particular, the focus is on the visualisation of the uncertainty level of the reconstruction process. Here, the reliability is defined through a gradient colour scale that is related to the different kinds of sources.

In order to add useful visualisations for transparency in these models, Nicolucci [33] suggests the use of a decision tree to represent the modelling process: each terminal node represents a final (alternative) stage, or an alternative reconstruction.

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[31] underlines that to visualise data there are two possible ways, the spatial visualisation and multiple windowed mediation of data and information. These could be translated for example with 3d visualisations, texts, graphs, windows with related sources accessible from the model (Fig. 10). Another hint is to use the “rigatino” restoration technique to fill the reconstruction lacunas allowing one to perceive the interventions. One point on which Brusaporci does not compromise is that of avoiding huge amounts of data, which would draw attention from the main object. The author does not mention visualisation tools for the general public. Soto-Martin [35] describes an approach to reconstruct and digitally render the pictorial heritage of St Augustine church in San Cristóbal de La Laguna, an interactive and immersive VR environment «for the enjoyment of all». Users can interact with the environment by activating markers, which will show a text box containing factual information (Fig. 11). The authors hope this environment can provide improvements in terms of student motivation, assimilation of content, and greater autonomy during working reconstruction and conservation processes.

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At last, the use of “transparent” visualizations will nurture a sense of cohesion between general public and restorers, researchers and museum professionals [5], when citizens will truly understand the elaborated process which lies behind the final reconstructions.

One of the ambitions of the research carried out by a project as PERCEIVE⁶ is the development of a user-friendly tool to facilitate and support the design process of digital experiences in alignment with PERCEIVE case studies and scenarios. Furthermore, the intention is to extend the applicability of the tool beyond the scope of the project. Two partners, the Italian National Research Council (CNR) and the German Fraunhofer Institute, have joined forces to pursue this particular endeavour.

Primarily intended to be of benefit to cultural institutions, educators in design courses, and professionals working in the creative industries, the tool offers a structured yet flexible framework for crafting engaging digital experiences. Its systematic approach ensures that all crucial aspects are considered and seamlessly integrated into the final product, while also fostering collaboration and igniting creative thinking throughout the design process. Our tool builds upon an already existing ideation card game, the VisitorBox⁷ which emerged from the GIFT Project⁸, funded by the EU's Horizon 2020 program. This toolkit was made available as open source, thus allowing for high customisation. Consequently, while maintaining the core elements of the original game, certain alterations were implemented to address the unique needs of our project and to ensure its full support of the PERCEIVE objectives. To this regard, an additional deck was implemented to include a set of cards specifically dedicated to PERCEIVE cognitive goals: Sense of Care and Authenticity. In addition to the physical card game, a digital counterpart in the form of a web application, with the same functionalities, is presently being developed and will be provided at the end of the project. The tool’s format notwithstanding, its fundamental nature is that of a card game. Its structure is based on key concepts and components such as cards, boards, and playing rules, with each stage and board of the game being conceived to mirror the phases of a design process. The session begins with the definition of the context, followed by the clarification of institutional and cognitive goals, ultimately converging in the design brief, which outlines the overall parameters of the team’s desired outcome. The game then progresses to the ideation and storyboarding steps, after which innovative thinking is encouraged by challenging the ideas just created in detail through a disruptive approach. This initial customised version of the VisitorBox was then employed for a preliminary assessment in a series of dedicated workshops involving all the project’s partners with the aim of finalising the design briefs for their respective prototypes. These sessions were held at CNR, the MANN and MUNCH Museums, and the HSLU between November and December 2023. All the valuable information and feedback gathered during these activities allowed the team to proceed with a more thorough redesign of the co-design tool. In February 2024, during a PERCEIVE meetup held in Florence at the CNR Institute, the researchers involved with this task met to brainstorm the new version and discuss its digital implementation. The further developments resulted in the release of version 0.9⁹ on April 17th of the PERCEIVE CoDesignTool. This new version introduced significant alterations to the workflow, the physical arrangement of the boards, canvases and cards, and their layouts and aesthetics overhaul. Thereafter, on the 24th of April, a testing session of this version was conducted at the University of Bologna, involving around 30 students from the Digital Humanities and Digital Knowledge Master’s Degree Program (Fig. 12).

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The inputs coming from their use of the tool were then translated into further refinements, leading to the release of version 0.9.1¹⁰ on the 30th of April. The latter was subsequently employed in two workshops: one held in its entirety remotely by MUNCH on the 7th of May and a hybrid session held by and at MANN on the 14th of May. In both instances, a digital version of the tool was implemented on Miro with the intention of facilitating online partners’ interaction and collaboration. During these sessions, only half of the co-design system was utilised, as the teams involved resumed their workflows from their previous meetings held in 2023. As of the time of writing, the CNR team in Florence and the Fraunhofer team are currently engaged in collaborative research and development activities, with the objective of further testing the paper version of the proposed solution while concurrently developing the dedicated web application. The preliminary wireframes are at present available for examination (Fig. 13) while a complete demo is expected to be released at the end of the PERCEIVE Project.

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