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Azulejo Research for the candidacy to UNESCO World Heritage status
Estudos no Azulejo Português para Candidatura a Património da Humanidade

> The Project > Plan & Methods

The Project aims at producing new knowledge to support the candidacy of the Portuguese faience azulejos integrated in constructions as World Heritage recognized and listed by UNESCO. Three vectors will be pursued:
i) the identification of Renaissance majolica azulejo panels as of Portuguese manufacture, separating those of doubtful origin from Spanish, Italian and Flemish productions;
ii) the identification, systematization and listing of the earliest tiled urban façades in Portugal and the setting, as far as possible, of their chronology and factory of origin; and
iii) the establishment of a permanent database of specimens of Portuguese azulejos together with information on their morphological and analytical characteristics, freely made available to researchers as a scientific basis for future studies on their history, evolving manufacturing technology, and on the sources of the raw materials used in their production. We call this archive of physical specimens azulejoteca (i.e. “azulejo library”).
All three vectors depend analytically on the portable X-ray fluorescence (XRF) spectrometer that has to be acquired within the project. The equipment proposed will incorporate helium injection and allow for the semi-quantification of sodium in the samples. After the completion of the project as proposed, this unit will be used to build further on the database of analytical knowledge on Portuguese azulejos.
By the end of the project the azulejoteca should incorporate at least 550 specimens, of which 50 fully characterized as to the composition of the glaze and pigments, biscuit and morphology of the glaze section. During the first four months into the life of the project the team will select these 50 first items. During this period, the document research for the identification and systematization of the first tiled urban façades will start since it too does not initially depend on instrumental means.

I- First vector- identification of Renaissance majolica azulejo panels of Portuguese manufacture.
A specific task will address the first vector, aiming at identifying the earliest Portuguese majolica azulejos and determine their technological ancestry. The study will deal with 16th century azulejos extant in Portugal but of doubtful manufacture. The method will join known historic sources and an analytical characterization of the azulejos in the panels. The basic technology used will be non-destructive energy-dispersive X-Ray Fluorescence. The high quality portable instrument able to detect s sodium (Z= 11) acquired within this project will be used on site to analyse the glaze composition, as well as any measurable coloured areas representing different pigments. Whenever there is detached glaze, small scales will be removed for electronic microscopy. There will also be made a morphological appraisal that may give clues: dimensions, colour of the biscuit, defects in the glaze, corner pin-holes (present for technological reasons in the Flemish productions [8]).
We have already obtained promising results, not only in the recent December 2014 campaign, but also in 2012 by Fares and by Mimoso et al. [7; 8]. These confirm that productions may be individualized and grouped based on characteristics obtained by analysis and observation. Statistical treatment of the results, in order to group the azulejos according to their characteristics, will subsequently be performed with data-mining techniques.
A subsidiary objective will be, by known historical sources, comparison and deductive reasoning, to try and determine the geographical origin of the technology initially used in Portugal- whether, as is often proposed by art historians, it was brought from Antwerp by immigrants, or whether it was acquired from the neighbouring Spain. Once the separation of productions is achieved, the earliest Portuguese examples will be tentatively compared with Spanish and Flemish productions, and conclusions drawn thereof.

II- Second vector- identification, systematization and listing of the earliest tiled urban façades in Portugal
A specific task will address the second vector aimed at identifying the earliest urban façades covered with azulejos in Portugal and establish on sound historical grounds their origin, use and evolution, particularly as respects the most important factories involved and the chronology of the successive decorative trends.
Mostly neglected by researchers and erstwhile overlooked by passer-byes, the tiled urban façades are however an important milestone in the use of azulejos in Portugal. Often used to give preeminence to the buildings from the others surrounding them, azulejos in Portuguese urban façades are a remarkable indicator of the importance the bourgeoisie attained in the social panorama of the 19th century. This can be assessed in the way these buildings were looked (or overlooked) at the time, often referred as houses of- or for- rich former emigrants (mostly from Brazil) of little formal education, for whom the ostentation of shining façades was a way to state their personal success. When excessively obvious, this architecture was often considered of bad taste by contemporary authors, nevertheless it thrived in such an unexpected way that the factories started to produce not only azulejos, but also other ceramic products such as statues to embellish the buildings. What is revolutionary in this use of azulejo is the application of a semi-industrialized product as social statement, to which the technical skill of the tiler added an important but usually forgotten quality.
Research will be conducted on the field, identifying façade coverings from known factories and chronological anchors (façades of known chronology) and registering their patterns. Instrumental analyses by ED-XRF will try and determine whether there are specific markers of the most important factories during the first three decades of urban spread. Town archives will be consulted to date tiled buildings and their alterations. These will be linked to the azulejo coverings. Early media sources will be reviewed to try and find mentions to factories or particular buildings, or engraved iconography. The final aim will be to establish the early history, both factual and decorative, of the use of azulejos as façade coverings in Portugal.

III- Third vector- Establishment of a permanent database of specimens of characterized Portuguese azulejos.
To this vector will correspond two different tasks: one related to the characterization- which will also feed information on the other two vectors of research; and one related to the physical setting up of the azulejoteca and making the data available digitally.
A full characterization will be made of 50 samples previously selected by the group of researchers in the project. Those samples will represent 400 years of azulejo chronology, since the 16th to the 20th century.
For the physical characterization, the dimensions of each azulejo will be measured and the manufacturing defects in the surface assessed. Polished sections will be prepared to measure the thickness of the glaze, assess its morphology and the dispersion of the pigments and register both optical and electronic images. Key techniques: Optical Microscopy (OM), Scanning Electron Microscopy (SEM).
For the chemical characterization, the composition of the glaze and pigments will be characterized from the glaze surface with ED-XRF. With the energy dispersive spectroscope (EDS) connected to the SEM, the glaze sections will be analysed, including any interesting inclusions. The biscuits will be analysed by ED-XRF and X-ray diffractometry (XRD). Key techniques: ED-XRF; SEM-EDS; XRD.
After considering the results, the group will choose a further 500 specimens to be analysed non-destructively within this task with ED-XRF. At least the glazes and any pigments used will be analysed and the results registered.
Each azulejo of the azulejoteca will be measured and set in a physical archive from where it will be easily retrieved for observation or further analyses. Any samples taken, including polished sections, will be kept in an archive easily traceable to the azulejos from which they were collected. The images (macroscopic, microscopic and electronic) and all characterization measurements will be available to researchers online through a digital database.
The images and results obtained from the measurements needed for the other two vectors will also be made available through the same database, even though physical specimens may not be available.
A subsidiary vector corresponds in general to the second mentioned above but applied to the renaissance of façades tiling during the two decades after 1954.