The Gnostic Craftsman

Courtesy of Philip Gaches

"Wow, this guy really knows what he's doing!"

This is a perfectly natural, expected reaction when listening to an accomplished cellist, a potter at the wheel, a smith at the forge or any master craftsman at work as our plasterer depicted here. What the aforementioned all share in common is that they all make an an extremely complex activity appear almost effortless. Their demonstration of competence commands immediate respect. We acknowledge that such mastery takes inner discipline, a substantial commitment of time as well as the accumulation of a fair bit of knowledge. Whereas English has only a few related terms, many other languages parse what we call "knowledge" into a number of nuanced meanings. In the process leading to mastery we can think of these manifestations of knowledge as incremental stages of development.

Second-hand, Given Knowledge

The Ancient Greeks placed the least amount of value on second-hand knowledge, doxa that is often translated as mere opinion. In its simplest form doxa may be nothing more than a narrative that we receive; that is to say, we "know" something because we heard about it. It's not the case that we've directly worked it out for ourselves or personally have done something. Rather, it consists in nothing more than a belief in or acceptance of something because it originates from an source in which we place trust. Closely related to doxa is the Latin term pistis, an intellectual and emotional acceptance of a proposition often translated as "faith" whereas doctrina referred to the articles or literal contents of faith (catechism) as taught by the Catholic Church. To "indoctrinate" maintains this negative connotation of the insertion of knowledge into an ostensibly intellectually empty human vessel.

In our more honest moments, I think we must confess that we depend upon this type of second-hand knowledge quite a lot. For example, whenever we read or listen to the news, accept reports regarding climate change from scientists or receive medical advice from our doctor, all of these reports represent doxa, forms of second-hand knowledge. The trouble arises because it's really easy to claim to know in a profound sense what in reality we've merely read or heard. In such cases what we're really doing is expressing a belief commitment. In our defence, there are tremendous constraints on how much we can personally learn and experience. We cope with this by outsourcing the problem socially and as long as our sources have real knowledge (are not mistaken) and are not trying to deceive or manipulate us it can be quite helpful, even necessary. However, we ought to be instinctively cautious of second-hand knowledge as mistakes, deceit or even our own misinterpretation tend to creep in and lead to paradox, literally "contrary opinions".

There are a number of ways in which craftsman can acquire this kind of second-hand knowledge. We  can certainly learn a few things about a given craft by reading about it. Likewise we can discuss it, having an experienced craftsman explain various aspects of the craft. Nevertheless, as craft is primarily experiential as opposed to being understood intellectually, literal and verbal explanations provide at best partial or low image resolutions of craft. Watching a craftsman at work or demonstrating his craft can add further insights whereas physically viewing, touching and measuring a completed work may yield a better understanding. Nevertheless, none of the aforementioned hold a candle to directly engaging in craft yourself.

First-hand, Acquired Knowledge

Two forms of acquired knowledge are necessary for craft. Both of these must be acquired directly yet are very different in nature from one another. Let's first address Theory. The Greek word from which our English word theory derives, theōria, literally means a kind of disinterested contemplation as a spectator may hold of a performance at a theatre. Just as there is no necessity or end goal of a performance, theory is a kind of knowledge for its own sake and pleasure. In Enlightenment language we might say that this species of knowledge is a relation of ideas held in the mind. The process of establishing truth claims built upon initial axiomatic presuppositions was known as analysis by the Greeks and scientia by the Romans. Both of these terms conveyed the concept of cutting apart mental constructs so as to reassemble them into ordered wholes. Geometry, deductive logic and arithmetic would be examples of such theoretical knowledge characterised by timelessness, universality and formality whilst being immaterial, that is to say creating no product nor engaging an action. Epistemology is one of the three main branches of Western philosophy that concerns itself with what constitutes knowledge. The Greek word episteme literally means to "stand over", implying a type of knowledge that stands removed, detached from the object or action of contemplation.

Courtesy of Hamza El Fasiki, Craft Draft

As craftsman we learn abstract systems of proportion and conventions when working inside of a given tradition. As a preeminent example, Classical architecture since at least the time of Imperial Rome has documented these systems into "canons", theoretical standardisations of its three principle orders, that is to say styles of building: the Doric, Ionic and Corinthian. Likewise, other architectural traditions such as Islamic, Vedic, Gothic, etc. possess their own conventional systems whose theoretical knowledge was retained and passed on through various iterations of trade guilds and apprenticeship programmes. Design is initiated from a theoretical point of origin and extended into three dimensions as represented by line, surface and enclosing volume. The elements, that is to say the smallest components of an assemblage, are all derived from fundamental geometric principles such as the circle and the square as well as the various conic sections: ellipse, hyperbole and parabola. A master craftsman (technitês) must be able to perceive, literally "thoroughly grasp" (Latin percipere), such theoretical principles.

A second form of personally acquired knowledge necessary for craft is of course Practise. Our English word derives from the Greek praktikos meaning "to do" or "to act". Practical knowledge is contingent upon what the Greeks called a telos: a goal or function inherent to a made object. Unlike theory, practice is inductively applied particular knowledge of matters of fact to fulfill some specific need or desire. It is thus an interested form of knowledge tied directly to material and action, a knowledge for something's sake as it were. Rather than any universal truth, practical knowledge seeks an arete, an excellence of value in the action or object made. Of interest the very word "philosophy" originally meant a "loving", philo of "skill in handicraft and art", sophos as characterised by its use in Homeric poetry of ancient Greece before its meaning was extended to include a love of wisdom in a more abstract and general sense.

This kind of practical "know how" was best captured in the Greek word techne, the Latin word artes carrying a similar meaning. Philosophers such as Socrates, Plato and Aristotle denigrated most craftsmen as mere banausikai techne, illiberal servants whose works were self-centered, of questionable merit and unbefitting of a gentleman. Aristotle in particular expressed that value rested only in the crafted object, not in the means of bringing the object into existence. This is a view that persists in contemporary times when far more value is placed on the end product and little concern given as to how that product is brought into existence. More often than not the process, tradition or training infrastructure required for skilled craftsmanship are ignored in favour of a dogged focus on bottom line price and schedule. By contrast, many Stoics held a more charitable view of skilled craft according value to practical experience, phronêsis as a virtue unto itself. All agreed that a master craftsman was identified by his sapientia, his ability to teach, furnishing a verbal or written account of the craft itself whereas a chief craftsman, architektôn further distinguished himself by his mastery of theory and practise combined with an ability to command others.

Innate Knowledge


In my own experience of teaching traditional plasterwork, the first thing I do is disabuse the students of the notion that I can teach them much at all. Like all traditional crafts, plastering is an embodied form of knowledge. Apprentices have to teach themselves or perhaps another way of stating it, they must unlock their already present potential to plaster thru repetitive action...craft as a form of ritual. I certainly can't plaster for the students; the most I can do is say a few words in the form of encouragement or critique and demonstrate actions whilst they observe. Learning a craft is more akin to a remembrance, the awakening of a capacity already present in the individual. The role of a master is less of a teacher as it is that of a spiritual guide. This type of knowledge has been described as empeiria, that is to say empirical knowledge. Unlike the aforementioned forms of acquired knowledge episteme which can furnish a verbal or literal account, empirical knowledge is internal, non-discursive and straightforwardly acted out. 

The ancient Greeks had a specific word for this kind of knowledge, gnosis. As you may already suspect this is the origin for our own English words "to know" and "knowledge". The sense of gnosis is quite intimate, more of a "knowing who" than a knowing how or what. It is the type of knowledge you'd have of a dearest friend or loved one. It's not a collection of facts about them, rather a deep connection that is shared.

To become an effective craftsman you must lose your mind. In the process of learning the student initially attempts to think thru and control his movements, ultimately a futile effort that leads to complete exhaustion. The student understandably wishes to know what to do in the sense of being informed of the correct materials, means and methods. Although there is a place for that, it is secondary in the learning process as information is always particular and soon becomes redundant. By abandoning oneself to the ritual of craft the student is rather transformed and an insight grows spontaneously from visceral, direct, embodied experience. For the master craftsman, knowledge sublimates into action, his knowing is making.


Contributed by Patrick Webb

Clayfest 2019

As a traditional plasterer based in the United States, I've been tangentially involved in natural building for many years, in both projects as well as gatherings. Of interest to traditional plasterers straw bale, light earth, adobe, etc. all involve coatings which typically include lime, clay or some combination thereof. However, natural building, contemporary traditional building and historic preservation (or what is called in the UK heritage and conservation work) remain parallel developing but largely separate sectors in the US. I've made a point in my writing and speaking to nudge these movements towards what I see as a natural convergence. To that end I was quite interested to see the state of affairs in the UK and to some extent the EU by attending Clayfest, an event sponsored by Ebuki and hosted by CAT, the Centre for Alternative Technology near Machynlleth, Wales. What I experienced was a bit unexpected.

The Encouraging

The aforementioned convergence between heritage, traditional new construction and natural building seems already well integrated in the UK and a number of the lectures were on this very topic. We heard form an heritage officer involved in organising training in traditional craft skills, a couple of traditional plasterers who work in and provide training to both the heritage and natural building communities as well as an academic from the University of York who's lecture was explicitly entitled, "Rethinking Sustainability as Heritage". Drawing from the vast inventory of traditional earthen buildings, stone masonry and timber framing in the UK and EU, I was left with the impression that the technical as well as embodied craft understanding of these materials and systems combined with the cross discipline communication puts these folks well ahead of where we are presently in the US.

The Disappointing

Day one was a lecture day. We sat in a lecture hall and listened to lectures...all day. There was supposed to be time for Q&A at the very end of each session but of course, as these things are wont to do, the speakers went overtime and hardly any audience participation occurred. I've no doubt that there were hundreds of years of collective wisdom within that room but the format did nothing to release it. I was really looking forward to the practical workshops of day two. However, the way these were structured also inhibited too much participation and there ended up being a lot more standing around than I'm used to seeing. These were nothing more I believe than structural impediments that could be easily addressed with some reorganisation. In that respect I think there have been some advances in the US with what is called the unconference or open schedule conference that allows attendees to think about what they might want to speak or hear about and participate in setting the agendas for smaller group discussions that reassemble later for strategy sessions.

The Troubling

You say you want a revolution 
Well, you know 
We all want to change the world - JL

The first thing I'll say is a bit intangible: I didn't feel welcome. That may not sound like much but it was jarring for me. I've always felt welcome in the natural building community. If I had a people, these would be them. Yet, something felt off from the moment I arrived. Where to begin...well, they're rolling out this train the trainers initiative and a common sentiment, practically an unofficial theme that I kept hearing over and over was along the lines of, "we have to train people to think like we do". I lack their certainty. I know I'm wrong (I strongly suspect they are too). I parade my ideas out there with the expectation and hope that I'll be told how wrong I am. Even if I'm right today, that answer will be wrong tomorrow; the world is dynamic, it's a living process. Oddly enough, none of the individuals seemed arrogant when talking with them one on one, yet this hubristic spirit hung over the entire proceedings.

You say you got a real solution 
Well, you know 
We'd all love to see the plan - JL

Getting a bit more specific, there were in my mind issues with some of the lectures themselves. The first of which was entitled, "What does an anti-capitalist building site look like?" I think one ought to be cautious about a negative title but fair enough, I personally hold the view that a capitalist economy is not going to be viable for much longer for humanity. I would've appreciated the speaker actually addressing the question and relating it back to earthen building. Instead we received an inundation of postmodernist philosophy, specifically a mash up of deconstructionism and feminism and poorly conveyed at that. A diatribe against an undefined patriarchy typified by white supremacy that painted two caricatures: the violent, aggressive, tyrannical masculine contrasted with the tender, generous and honest feminine. The solution? Again, the question was never addressed.

You tell me it's the institution 
Well, you know 
You better free you mind instead - JL

A second lecture, "Integrated technical training for women in northern Nicaragua", was delivered far more coherently and perhaps for that very reason, was more disturbing. Actually, the lecture had very little to do with technical training beyond its practical use as an instrument for feminist activism. I've no doubt that many women, have a hard life in Nicaragua and made even more so because they are women. Furthermore, I've no objection to support folks who are trying to develop their own capacities. It's the entire reason I teach, speak and write. However, it's one thing to support someone's personal development and another to indoctrinate and activate the young as avatars of your own ideology. It came across to me that the speaker was dripping in condescension of Nicaraguan culture. It's the same disastrous attitude the West has displayed internally and towards the rest of the world for almost a millennia, sending out our missionaries to convert and "civilise" the masses. That kind of "helping" has bred a maelstrom of resentment. Replacing the church with a secular ideology doesn't change the basic disposition.

But if you want money for people with minds that hate 
All I can tell is brother you have to wait - JL

In conclusion, I'll say this: the natural building movement grew into existence from the ashes of lost tradition, it came about organically. If we now attempt to graft to it postmodernism, feminism, socialism or any other rationally constructed ideology, it won't be racists, misogynists, industrialists or any "other" that will destroy the movement from without, but tragically it could very well be us that poison it from within. Please, let's not let it come to that.

Don't you know it's gonna be  
All right - JL

Incidentals

I noticed many folks at Clayfest had the pictured symbol on T-shirts or as badges. The extinction symbol, an hourglass within a globe, has been taken on by a newly formed social movement, Extinction Rebellion. I read their manifesto which actually came across as measured and reasonable. I'll be keeping an eye on how they interpret this manifesto and develop.


Contributed by Patrick Webb

Natural Building & Traditional Craft

Initially published on Traditional Building Magazine online February, 4th 2019

Last autumn I was passing through the Shenandoah Valley of Virginia and decided to drop in on a good friend of mine, traditional timber framer Jordan Finch. Jordan and I had taught together at the American College of the Building Arts in Charleston, SC. When I arrived he was busy hand chiseling and fitting the mortise and tenon timber joints for a project with fellow timber framer Robert Laporte. Robert and his wife Paula have a company EcoNest that specialises in design build of homes, traditionally timber framed with light clay straw infill, that are typically lime plastered inside and out. I gave them a hand for a day and ultimately Robert recommended me to the homeowners for the plasterwork. The whole process was fascinating and I'll endeavour to share from this experience the type of home that is today possible by the combination of highly skilled means and methods of traditional craft with the truly sustainable ethic of a contemporary natural building approach.

Timber Framing and Light Clay Straw

Robert Laporte has a young apprentice

You can't get more sustainable than responsibly cultivated and harvested timber. A properly constructed and maintained timber frame structure can endure for centuries. Timber framers are really architects in the original sense of the term, master (arkhi-) craftsman (tekton), who design and undertake the construction of the primary structure that holds the building up. The next generation of Finches were in on the action as well. Apprenticeship can't start too early on the long road to mastery!

Light Clay Straw Infill

A benefit of timber framing is that almost all of the construction of the members can be carried out in shop conditions and brought to the job site for a rapid assembly. Lincoln logs for grown ups! The next phase of the project was to shutter and infill the timber framing with light clay straw. Light clay straw is a contemporary adaptation of some very ancient traditional wall assemblies: cob and rammed earth. Similar to cob the mix is a combination of loam (sand and clay) and perhaps a bit more straw or other woody fibres. That cob-like mix is then stuffed and lightly tamped between form not unlike rammed earth but not quite as dense. The thermal mass of the loam and the thermal insulation of the straw make for a very interesting "dynamic insulation" that can contribute significantly to a very comfortable indoor environment in a variety of climate conditions with a minimum of energy consumption. A similar approach was used for most of the earthen floors which utilised a mix richer of clay, finer fibres and finished with linseed oil. Next up: loads of plastering with another good friend, Rob Wozniak and his team from Preservation Works!

Interior Lime Rendering and Clay Finish

For the interior perimeter walls we installed lath followed by removable wooden grounds that we used for scratched render followed by applying and leveling the brown coat with rods and compressing with wooden floats the following day. The plaster mix was a combination of two local sands, hemp fibres for tensile strength and Lafarge Natural Hydraulic Lime as the binder. The first week all of the preparation and scratch render went up and with the hydraulic properties of the lime setting in we were in good shape for the next float coat and clean up by week two. Lime plasters were the perfect choice as they are exceedingly durable and share the moisture permeability of the light clay straw substrate.

Whereas all of the interior perimeter walls received lime plaster, the inner walls had been framed and received drywall. For the finish we applied American Clay plaster as a nominal 1/8" veneer over both surfaces, the lime plaster and the drywall, for a unified finish. Lime and clay are both traditional materials, practically inexhaustible resources that are completely non-toxic. The means and methods of application go back to the dawn of civilisation: hawk, trowel, rods and floats. The work is physical but not brutal on the body. Essentially plastering makes for good exercise!

Exterior Lime Stucco

The exterior lime mix and application was basically the same as for the interior; sand, hemp fibre and hyraulic lime applied in a scratch and brown coat. However, instead of finishing with clay, the final coats were of lime stucco as well pigmented with mineral tints. The traditional design principle of "having a proper hat and a good pair of boots before going out in the weather" was followed here. There was an impermeable stone water table up to two feet to prevent rising damp or backsplashing as well as extended eaves to prevent the possibility of streaming water that might erode or discolour the stucco finish. Very smart application of embedded traditional wisdom as this part of the country can have some brutal winter and spring weather including blizzards, ice, sleet and heavy rains.

Hand Carved Islamic Dome

Included in our commission was the design, construction and installation of an enriched plaster dome of Islamic geometric design for the "mihrab" or private chapel of the owners who presented me with a rendering of an hexadecagram, a 16-sided star polygon as a point of departure for the design. The first challenge was to determine the surface to receive the design, to research what kind of curvature for the dome was possible given the architectural constraints of the room height, the potentially obstructing rafters above and even the thickness of the dome itself. We managed to squeeze out the most curvature possible with a profile generated by a three-centred arch, an approximate ellipse.

The hexadecagram pattern could now be adapted for the determined surface. This was all carried out traditionally, geometrically with compass and rule. The initially provided design was modified, the proportions of the 'safts' or petals of the star-like tessellation were adjusted to produce a more harmonious composition and the entire pattern was reduced in scale so as to be fully observable from a prostrate position on the ground. A calligraphic element, "ﷲ‬, Allah" was placed in the direction of Mecca to provide orientation for prayer.

Translating the interlaced pattern from a scaled two dimensional drawing to the three dimensional surface of the dome was another important step involving more geometry. The dome was to be cast; this meant that the "void" had to be first extruded in plaster. Onto that inverted surface the pattern was carefully and methodically transferred, physically inscribed utilising several methods to verify its precision. This accomplished, the casting of the dome in a relatively thin shell of plaster could commence.

Islamic geometry participates in a  universal tradition of sacred geometry. Principles of the sacred feminine in harmonious relation with the sacred masculine were intrinsic characteristics of the tessellated dome that I sought to augment. For example, the "void" of the dome can point to the vault of heaven but has a perhaps stronger correlation with the universal "womb", the unseen and unknown mystery out of which all emerges. Rather than being considered empty or being nothing, the void symbolises that which is as of yet undifferentiated...potential itself. The gentleness and ethereal nature of the void is contrasted with the rigourous order, the imposed and revealed pattern of the tessellation.

For the enrichment of the surface we chose to further accentuate these principles of softness/sharpness, darkness/light, the sacred feminine and masculine. The oculus at centre surrounds a lightwell, literally bringing the light of the sun to be the focal point of the design. The tessellation continues to emanate from there in successive waves. The sixteen pointed star received a soft dimpled pattern representative of the sacred feminine, next contrasted by the sharp "flamed" texture hand gouged with wood chisels. The safts of the tessellation were so proportioned as to provide balance between these soft/hard, feminine/masculine elements. The end result is an harmonious composition that takes disparate, contrasting elements and interlaces them together into its own symbolic "universe", a single turn of the divine compass, encompassing quite literally the sacred feminine and masculine, seen through the symbol of unity, the perimeter of the circle through which it is entered.

Contributed by Patrick Webb

Buon Fresco (Fresco)

Villa dei Mistieri, Pompeii

La Villa dei Misteri en Pompeya, la Villa Farnesina de Rafael, la Capilla Sixtina de Miguel Ángel. Todos estos son ejemplos icónicos clásicos y renacentistas de arte decorativo estrechamente relacionados con la arquitectura. La vitalidad duradera de estas obras maestras del mundo antiguo es atribuible en gran medida a la naturaleza del medio que comparten: el buon fresco.

Los verdaderos frescos son el resultado de pintar pigmentos minerales u óxidos en una superficie de cal todavía húmeda o "fresca". Los pigmentos penetran en la cal y se  onvierten en parte integral del recubrimiento a medida que se seca y cura. Si está protegido  por la misma construcción, un fresco puede durar indefinidamente.

Historia

Se pueden encontrar evidencias de lo que muchos piensan, de que el asentamiento humano más antiguo descubierto es Çatalhöyük, con fecha de alrededor 7500 a.C. Gran parte de lo que sabemos de esta civilización antigua, se conserva en pinturas al fresco de caza, cría, mapas y motivos geométricos de expresión aparente puramente artística. Las grandes civilizaciones posteriores, como los egipcios, el valle del Indo, Harappan, la Grecia clásica y Roma, continuaron haciendo un uso generalizado de los frescos en sus respectivas culturas.

Nuestro patrimonio cultural artístico y arquitectónico, aquí en occidente, ha sido fuertemente influenciado por la antigua Roma. Los romanos dejaron muchos ejemplos bien conservados de frescos, como los que se encuentran en Pompeya, Herculano y el palacio de Nerón, la Domus Aurea... Además, podemos estar muy agradecidos de que el ingeniero y arquitecto romano Marcus Vitruvius Pollio dedicó un libro completo en su obra de múltiples volúmenes, De Architectura sobre la preparación de los soportes, de la cal y de los pigmentos para pintar frescos, este incluye pautas de aplicación y comentarios coloridos y de opinión sobre cómo consideraba la estética excesivamente decadente de su época.

Los escritos de Vitruvio lograron su publicación y circulación a principios del siglo 15 en los comienzos del Renacimiento. Los artistas del Alto Renacimiento como Rafael, Miguel Ángel  y Leonardo da Vinci estudiarían y ampliarían los ejemplos romanos para convertirse en grandes maestros por derecho propio. Este artículo sirve como una introducción a las técnicas básicas de pintar frescos: el enlucido y la pintura al fresco.

El enlucido

Curiosamente, los ejemplos antiguos fueron aplicados principalmente en revocos de tierra. En los climas secos de Egipto y en la región de Media Luna Fértil, el combustible para quemar la cal a alta temperatura era limitado. Sin lugar a dudas, la cal era considerada un material muy valioso y, a menudo, solo se usaba como una capa de acabado en la que se pintaba el fresco. 

En Grecia y Roma se convirtió en una práctica común revestir con cal directamente sobre paredes de mampostería para obras importantes, los romanos a veces optaron por aplicar la cal en listones de madera en los techos. Afortunadamente, los principios registrados por Vitruvio se utilizaron en el Renacimiento y todavía se aplican en la actualidad. El método básico para lograr una buena base siempre implica una capa inicial con una capa arenosa y rugosa e ir aplicando posteriormente capas de arena más finas y terminando con una capa de acabado delgada y suave. El proceso debe mantener suficiente humedad en el sistema para que el artista tenga tiempo suficiente para pintar la capa de acabado.

Trullisatio. Vitruvio describe con gran detalle esta capa base rugosa compuesta de cal, arena y piezas más grandes de terracota rota. Una función similar se logra con lo que llamamos capa base. Sirve como un una capa intermediaria entre la mampostería o el soporte de listones, proporcionando una buena adherencia mecánica para la siguiente capa.

Aricciato. Vitruvio recomendó 3 capas con cal mezclada con arenas cada vez más finas. Esto corresponde a nuestras capas de fratasado. Cada capa se fratasa con una llana de madera para comprimir y endurecer la superficie. Debido a que la cal necesita tiempo y humedad para curar cada una de estas capas, debe humedecerse diariamente y dejar reposar durante aproximadamente una semana antes de la siguiente capa. Siguiendo el precedente del arquitecto del siglo XV, Leon Battista Alberti, los artistas del fresco del Renacimiento y contemporáneo redujeron esto a una o dos capas.

Intonaco. Una vez más, Vitruvio recomendó 3 capas con cal, esta vez mezclada con polvos de mármol cada vez más finos. Existe evidencia arqueológica de que las obras romanas de calidad siguieron al pie de la letra estos consejos, lo que resultó en unos espesores totales de hasta 2 pulgadas. El sistema de capas de acabado en el Renacimiento variaba al igual que las que se aplican en el dia de hoy. Un método italiano contemporáneo es aplicar una capa de cocciopesto (arena de terracota agregada al marmorino), comprimir con una llana de esponja e inmediatamente aplicar un acabado de marmorino. Este acabado endurece en aproximadamente 2 horas, dejando entre 6 y 8 horas de tiempo de trabajo para pintar el fresco.

Pintado del fresco

Una vez finalizada la última capa del revestimiento, el pintor debe comenzar rápidamente el trabajo de aplicación del diseño antes de que la humedad se evapore de la cal y bloquee la entrada de pigmentos. El tiempo de trabajo en buon fresco varía con la humedad del aire y el subsuelo, pero generalmente se puede suponer que es de alrededor de 8 horas.

Por cortesia de

The Academy of Classical Design

La preparación para pintar es clave; El diseño debe entenderse bien, los colores deben estar preparados y listos para su uso. Los pintores de frescos en el pasado normalmente tenían un pequeño equipo de asistentes para hacer el enlucido, moler y mezclar los colores, y estar a mano en caso de que se tuviera que rehacer un área. Es esencial haber realizado muestras de prueba de colores y tintes para juzgar cómo se verán secos, ya que muchos colores cambiarán drásticamente, especialmente si se han mezclado con "lechada de cal", que es transparente pero se seca como un blanco luminoso.

Una vez que se ha aplicado el diseño, el pintor comienza a colorear de manera deliberada y económica, como si fuese acuarela o pintura al temple de huevo, utilizando el color del fondo como el valor más claro, aunque la lechada de cal también se puede usar como blanco y como base para los tintes de colores. La paleta para buon fresco está limitada a esos colores que son compatibles con la química de la cal; varios colores populares no están disponibles para el fresco, pero la paleta es bastante variada, como lo atestiguan los antiguos murales de Pompeya. Los colores generalmente se mezclan moliendo a mano los pigmentos puros con agua utilizando una mano de mortero, de modo que los pigmentos que son tóxicos, como los colores de cadmio, deben usarse con gran precaución. También hay nuevos colores premezclados disponibles que se pueden usar, aunque algunos puristas los rechazan. A medida que se seca el enlucido, los colores finales salen a la superficie y una capa muy delgada de carbonato de calcio se eleva hacia la parte superior para encapsular y proteger los pigmentos en una capa muy fuerte y que no amarillea. Protegida del agua, la pintura de un fresco durará indefinidamente. Hay técnicas para pintar después de que el enlucido se haya secado (llamado "secco"), pero eso tendrá que ser un tema para otro día.

Con miras al futuro 

 

Los frescos tradicionales que usan cal pura como se practica en el Renacimiento requieren un proceso prolongado que lleva varias semanas debido a la necesidad de esperar a que se cure cada capa de cal. Una alternativa práctica es utilizar cal natural hidráulica para las capas de fratasado. A diferencia de otros revestimientos o cementos, las cales hidráulicas naturales no contienen compuestos dañinos que luego podrían causar eflorescencias o dañar el fresco. Las cales hidráulicas naturales logran un curado parcial suficiente para recibir una capa posterior después de una noche. La aplicación completa de las capas se puede lograr en 3 o 4 días con un espesor total de 25 mm”.

Otro sistema de capa base que se está investigando, es para usar directamente sobre paneles de yeso, consiste en un mortero de arcilla, yeso y cal mezclados. El yeso proporciona una buena adherencia, mientras que los componentes de cal y particularmente de arcilla retienen la humedad durante muchas horas, unas propiedades ideales para una base de revestimiento que va a recibir el acabado Intonaco y la pintura al fresco.

Por cortesia de

The Academy of Classical Design

 

Conclusión

La belleza intrínseca y duradera siempre ha sido una razón de peso para considerar la pintura al fresco. De modo que con los avances en los diferentes tipos de materiales, los pigmentos más seguros y los gastos reducidos de esta técnica, hacen que el fresco no solamente sea una curiosidad caprichosa del pasado, sinó un medio contemporáneo y vibrante accesible para todos los artistas, ¡incluido usted!

Este artículo fue escrito por Patrick Webb y Steve Shriver

Traducido por Anna Castilla Vila

Stuc Pierre (Estuco de Piedra)

Por cortesia de Plâtres Vieujot

El Stuc Pierre, es un acabado de enlucido a veces hecho con moldes que imita la piedra ashlar. Está hecho con una mezcla de yeso, cal hidratada (opcional) y un árido pulverizado de la misma piedra original a la que se pretender imitar.

Historia

Casa de Sallust
alrededor de 100 AC

Aunque existen numerosos ejemplos de imitación de piedra hechos con estuco entre varias  civilizaciones antiguas, fueron los Griegos y los Romanos quienes perfeccionaron este arte. Los griegos, desarrollaron técnicas de estuco para emular directamente su monumental arquitectura de piedra. Por lo contrario, los romanos, mostraron una interpretación más realista en desafío a las normas griegas. Los Romanos manifestaron una preferencia por su uso en ornamentos interiores, y aprovecharon la ventaja de la libertad física que ofrece el estuco para crear decoraciones que incluso no serían posibles de realizar con piedra.

En la europa medieval, el arte de Stuc Pierre disminuyó e incluso llegó casi a desaparecer por completo debido a que fué trascendido por la imitación a la piedra con técnicas de pintura al temple y a la cal. Pero durante el renacimiento italiano empezó un resurgimiento de la imitación de la piedra con estuco de cal. Un ejemplo notable es el Palazzo del té del siglo XVI, en el exterior de Mantua, donde se desarrollaron a la perfección cornisas, frontones y una variedad de adornos en homenaje al prestigioso travertino romano de los Palacios de la antigüedad.

Palazzo del Té

Por cortesia de Plâtres Vieujot

Francia pronto lo siguió, en los siglos XVII y XVIII. Stuc pierre, basado en yeso predominaba en los interiores públicos durante el siglo XIX adornando áreas comunitarias como entradas, halls o escaleras. No solo creaba la ilusión de una arquitectura clásica monumental en piedra, sinó que también proporcionaba la durabilidad, una durabilidad comparable que ha permitido disfrutar de muchas instalaciones presentes hasta el dia de hoy.

Por cortesia de Plâtres Vieujot

Debido a la amplia disponibilidad de yeso en toda Francia, Stuc Pierre era de uso común en regiones tan diversas como la costa de Normandía, Provenza, Borgoña, los Pirineos y la Costa Azul. Particularmente en París y en la Île-de-France, no es raro ver ejemplos existentes de fachadas representadas completamente en Stuc Pierre o en combinación con Stuc Brique, una técnica similar en la que los agregados de piedra pulverizada se reemplazan por polvo de ladrillo. Stuc Pierre fué tradicionalmente aplicado sobre un soporte de ladrillo o mampostería. Con el advenimiento de la construcción de hierro y acero a principios del siglo XX, Stuc Pierre se usaría cada vez más sobre la malla para preservar la apariencia de una fachada arquitectónica clásica.

Mise en OEuvre , Aplicación

El primer paso es la selección precisa de la mezcla. Para trabajos de restauración, se diseña el mortero para el tipo de piedra a imitar. La nueva construcción permite una gran libertad artística. A diferencia de la cal o el cemento, el yeso es un material autoaglutinante. Agregados, tales como piedra triturada,
ladrillo o arena no son necesarios para el rendimiento del revestimiento, pero se agregan para los fines de la invención. Se puede también agregar cuentas de vidrio, serrín, conchas marinas y fibra de lino para la expresión artística.

Al igual que con cualquier revestimiento, la limpieza y la estabilidad del soporte son muy importantes. Cuando se utiliza en el exterior, hay que prestar atención a los diferentes diseños arquitectónicos. Los aleros, los entablados y las hiladas voladas, son importantes para eliminar el agua de la fachada y evitar la transmisión localizada. Las superficies horizontales que por lo general ocurren en los frontones, las aberturas de las ventanas y puertas deben estar correctamente a nivel. Una capa freática, como por ejemplo; una piedra densa e impermeable en la base, evita que el agua suba a la acción capilar. La adherencia a unas pocas soluciones sencillas y muy exitosas hace que un trabajo hermoso perdure por muchas generaciones.

La mezcla se puede hacer a mano, con una mezcladora o con una hormigonera. La aplicación exterior se puede hacer en una sola capa o en capas sucesivas con un mínimo espesor total de 30mm. En interiores, el espesor se reduce a un mínimo de 12mm-19mm. Es posible la aplicación sobre albañilería, sobre listones de madera o sobre paneles de yeso. En todos los casos, se pueden utilizar las herramientas tradicionales de estuco y yeso, como la paleta, la llana, el fratás, regles, herramientas de esquina, etc. Hay diferentes diseños de acabado exteriores, cornisas hechas in situ, molduras y ornamentos.

En el acabado de estuco de piedra se confía en el artesano experto para desbloquear el gran potencial artístico del material. Una cuchilla de acero francesa o paleta Berthelet se usa tradicionalmente en la superficie, para quitar el exceso de mortero y nivelar la pared, exponiendo así los hermosos agregados que contiene. Se pueden utilizar tratamientos adicionales como el lavado, el pincelado, el pulido o el lijado para lograr los efectos deseados. Para el corte de uniones se utiliza una herramienta de la vía del ferrocarril tradicional o Chemin de Fer. Las juntas pueden dejarse abiertas y lisas en un patrón Ashlar o rellenarse con material para dar un efecto de mortero.

Sostenibilidad

Por cortesia de Wright Architects

El Stuc Pierre es valorado en el mercado de la sostenibilidad. En la UE, el estuco de imitación de piedra se usa comúnmente en la construcción de balas de paja y de cal y cáñamo. El yeso tiene una energía de fabricación relativamente baja, producida al calentar el yeso crudo a aproximadamente 300°F. Las adiciones de aglutinantes de arcilla, fibras de cáñamo y agregados recuperados o reciclados pueden reducir aún más la energía incorporada. Tradicionalmente, un pequeño porcentaje de cal hidratada se añade a la mezcla aportando alcalinidad y resistencia natural al moho. Todos los materiales utilizados en el estuco piedra son minerales o renovables, no tóxicos y libres de VOC. Además, la porosidad del recubrimiento garantiza una cobertura transpirable que aprovecha al máximo la transferencia del calor y reduce puentes térmicos.

Conclusión

Me gustaría agradecer a Joël Puisais, de The Compagnons du Devoir y a mi compañero Marc Potin de Plâtres Vieujot por las referencias históricas de esta publicación. Plâtres Vieujot fue fundado en 1880 y sigue siendo el único fabricante privado de yeso en Francia. Puede encontrar más información en su página web: http://www.platre.com/platre/


Escrito por Patrick Webb
Traducido por Anna Castilla Vila