THE PALEOLITHIC WALL PAINTING

Post 677–by Gautam Shah

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The wall paintings (upper palaeolithic eras) began as a medium of expression -a ‘story’ telling exploit. It was not a decorative art for a place, but a ceremonial craft in a space. The paintings were in deep caves as well as open sites. Bhimbetka, India, sites shows human occupation for more than 100,000 years, but earliest paintings on the cave walls here date back just 30,000 years ago.

Bison Cave of Altamira

Upper Palaeolithic period began roughly around 40,000/60000 years ago and lasted through the Pleistocene ice age, which is believed to have occurred near 8,000 B.C. This period was marked by the rise of Homo sapiens and their ever-developing ability to create tools and weapons.

Bheem_Baithika_Caves_Paintings_(7)

The cave sites were difficult to access but were perhaps special and visited by several generations. The caves were deep and dark and artists worked with lamps and torch lights. The paintings were made on walls, ceilings and even floors. Many of the locations and surfaces were acutely irregular. Artists had to work in squatting lying position or use elaborate scaffolding to reach the heights. The scale of the job was stupendous. Deep cave paintings have survived, whereas open location paintings have generally been destroyed.

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At Bernifal in the Dordogne, the mammoths are painted 20 feet up. Some of the bulls at Lascaux are more than 20 feet long. The big cave vault at Lascaux, known as the Picture Gallery, is more than 100 feet long and 35 feet wide.

Lascaux_painting image by Prof saxx

The cave art consists of simple impromptu works as well as grand executions. The first types were perhaps executed by amateurs or apprentices, and the second by masters. To sustain projects of such scale, the master artists were helped by a retinue of assistants and the community. The assistants helped in erecting scaffolding, preparing the surface to be painted, mixing colours, devising brushes and other colour application tools, feeding animal fats to lighting torches, provisioning food and water.

Bhimbetka_Cave_Paintings

The cave artists have shown very high degree of professionalism. The compositions, understanding of the animals’ anatomical details, animals’ form, dynamism and movement, all represent a keen sense of observation, experience and discipline.

The limited choice of colours has been overcome by the masterly expression of form. There is consistent economy of line. The textural and tonal qualities do not represent the light and shade, yet suggest the depth through colour differentiation (recognizing the ‘grey tone value’). At places existing substrate textures have been exploited. The scale and distribution of objects within a composition do not follow a visual proportion system, yet prioritize the elements of the story.

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Wall painting began as a line drawing. Lines were frequently scrapped through a sharp edged tool. The etched lines perhaps helped in retaining the charcoal or soft stones rubbings. Such art works, as the primary responses were impressed on whatever interior or exterior surfaces that were available. However, it was realized that more permanent work can only be created in a protected space. The caves space and its environment stimulated a spiritual experience for the portrayal. The spaces must have been favoured by several generations, as some of the paintings have been modified repeatedly over thousands of years. The earliest works are refined compared to later works or modifications.

Paintings_from_the_Chauvet_cave_(museum_replica)

There is nothing to suggest that the art was a setting of a ceremony. There is no depiction of a sacrifice, or a master of ceremonies like a priest, sorcerer or a witch-doctor. The paintings also have no images of the surrounding terrain or the vegetation of the time.

Bison-Cave-Painting-Altamira-Caves

The palaeolithic wall art consists of three main categories of subjects: animals, humans and signs (abstract or unexplained). The animal figures are the most detailed and naturalistic representations, but drawings of humans are rare and perfunctory. ‘In the case of Chauvet, predatory or dangerous animals dominate, while in Lascaux the main representations are of large herbivorous mammals’. At caves across various geographic locations the animals include: woolly rhinoceros, lions, bison, horses, aurochs, bears, reindeer, wisent, and giant deer and hyenas. At places species which were then extinct (as per the time dating technology), are also painted. Some of the most common species such as the reindeer do not find any representation, though bones have been found in the cave. The wall art also includes prints of spray painted hands, with abstract interconnecting lines.

Lascaux,_Megaloceros

The abstract signs are said to be representing the perception of night skies, of stars etc. Some forms of visual effects of movement or vibrancy (experienced in limited illumination) were perhaps included by use of florescent dyes, and slightly shifted images.

MATERIALS and TECHNIQUES

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Wall art of upper Palaeolithic age in the early phase did not have any surface preparation except scrubbing off the loose particles and dust. Selected surfaces were away from flowing or leaching water. Early phase drawings were done in line work with charcoal, but compared to this the carbon black, a deposit over an animal fat burning lamp had better binding and colour saturation. Lines were also scratched or etched by a sharp tool and done over with a black colour. Scratching the surface also ensured better colour retention. Later renderings (filling up the colour) with red ochre (Iron oxide from Haematite) and black was done. In the later phase (25000/20000 BC) other colours such as yellow and brown were added to the palette.

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In the initial phase dry colours were rubbed over the surface. In the later phase colours were ground with water and additives like blood, urine, eggs and animal fats. The additives improved the bonding, increased the viscosity (to prevent run off the surface) and reduced the drying time (allowing application and rendering effects). Learning also included: how to prepare intermediate shades (orange and browns), prevent algae like growth, avoid colours that fade over an age and moisture bleeding of colours and additives. Colours were mixed Calcium containing water or nodules to improve fixing.

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The colours were ground by rubbing them over a rough surface, and also through pestles and mortars. At Lascaux, some 158 different mineral fragments were found. Shells of barnacles and human skulls were used as containers for ground pigment pastes. Colour was applied by brushes, twigs and fingers. Colours were also put on by spraying through mouth and blow pipes made from bird bones, and by daubing with hands, fibrous pads and soft skins. Colours were sprayed over hands as the stencils to perhaps mark the participation or visitation.

altamira Hand spraying but of post original work period

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RHETORIC in DESIGN -issues for design -16

Post 653 -by Gautam Shah

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Rhetoric is the ‘art of speaking or writing effectively’. (Webster’s Definition) Aristotle describes it as ‘the ability or means of persuasion’. He describes three forms of rhetoric: Ethos (distinctive spirit of a people or an era), Logos (the logic and supportive evidence behind an argument or a reasoned discourse), and Pathos (represents an appeal to the emotions of the audience, and elicits feelings that already resides in them). Rhetoric is used in literary and verbal expressions, by using things that are familiar, but less acknowledged in common usage. In literary and verbal expressions rhetoric is exploited by construction (of the language form) and reinforced through the means of delivery such as rendering diction and graphics.

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Literary and verbal expressions generate instant and consistent impression over their audience or followers. Designed objects like arts, crafts, architecture, graphics, products, etc. however, do not carry an immediate or intense message of persuasion. A design has a persistent delivery, but very variable in content. It gets actualized in many different scenarios.

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Emotions through rhetoric ‘have specific causes and effects’ (Aristotle -book 2.1.2–3). Such dialogues however, do not exist between designers and connoisseurs. ‘Aristotle posits that along with the pathos (an appeal to the emotions of the audience), a speaker must also deploy good ethos (distinctive spirit of a people or an era) in order to establish credibility’. Philo distinguishes between two different types of logos 1 Prophorikos (the uttered word) and 2 Endiathetos (the word remaining within). In case of design-objects, the later one is relevant, as the rhetoric of design is always latent or potential.

640px-Henri_Rousseau_(French)_-_A_Centennial_of_Independence_-_Google_Art_ProjectRhetoric is means of expression or conveyance. In Literature and utterances it gets reinforced through linkages or examples, and altered through feedback from the audience. Such immediate response is not possible for Art, craft or architecture, and if any, it arrives as feed-forward in the make up (training and experience) of the creator. The design feed-forward chiefly relies on the visual rhetoric like books, site visits, media images, etc. But, it is impossible to perceive here ‘one cause to one effect pattern’. Other sensorial inputs like touch, smell, taste, aural, etc., historically had alogical legitimacy. Once a design actualizes, the feedbacks may arrive as historical realizations, but in different time and context. So designs can ‘have traceable past, but uncertain future.

Interior_of_a_revolving_space_station_(artwork)

It is often claimed that visual literacy is of recent origin, when we ignore the mediums of expression and conveyance, which have been with us since primitive age. Wall murals’ images were visual rhetoric, well ‘read’ and capable of arousing Aristotelian pathos (an appeal to the emotions of the audience). Some examples of visual means are charts, graphs, diagrams, photographs, movies, printed media, etc. but though these arouse the pathos but not always as instant response.

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Visual Literacy

The study of visual rhetoric is different from that of visual or graphic design, in that it emphasizes images as sensory expressions of cultural meaning, as opposed to purely aesthetic consideration. (Kress, Gunther, and Theo van Leeuwen. Reading Images: The Grammar of Visual Design. New York: Routledge, 1996.).

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The Design objects like architecture poses a statement only after their making, or on being used as an ‘artifact. Vitruvius stated that a work of architecture is a matter of ‘invention, arrangement, memory, delivery, and style’, and the process was perceived to be similar, to the Aristotelian way of putting together a speech. Design creation is very circumstantial, meant for a client, functions, site, regulatory framework, financial restraints, etc. It, however, needs to be tempered by arrangement, assimilation or composition of many different elements and considerations. These, together offer a holistic character, but realizable only after the creation. Rhetoric in design, if any, is in the design feed-forward, and after its avatar through the feedback. The feed back spreads over a very long period, sometimes after the original entity is destroyed. The Aristotelian depiction of Rhetoric as ‘the ability or means of persuasion’, for designed objects like architecture remains vague or conjectural.

Bidri_craft,_craftmen_at_work

The ability or means of persuasion were reasonable for artefacts conceived and made by the same person. But modern designers generate designs through surrogates or representations, and transmitted to makers or assemblers as schema or specifications. The communication through a schema is an order for execution, but certainly not for persuasion or concurrence. The instructions, if, any are non-personal and distanced in time. Some designs are too involved with the clients or stake-holders, but many others are panoptic. Designers are self-absorbed to care for persuasion or confirmation of anyone. Rhetoric exists, but as statement of non-confirmation.

Deconstruction Ways by Isidro Blasco

Design disciplines are categorized in four major domains: Graphic Design (Real and abstract -symbols communication), Products Design (objects, artefacts, craft-items), Services Design (software, interaction, stake holders) and Empathetic Design (social concerns).

McKeon, Buchanan state the understanding of design, as of symbols and images1, physical artifacts2, actions and activities3, and environments or systems4.

Architecture Confluence Lyon Deconstruction

Build-Designs are perceived at Two levels. First level consists of assembly of elements like signs, patterns, or images, and the organizational discipline. At another level, there is holistic form that is conceived without any elemental identities.

Kirtimukha_sculptures_on_shikhara_(tower)_of_Amrutesvara_temple_at_AmruthapuraThere are few characteristics common to both the congregated and totalitarian forms. Design, in part or as a whole is an allusion to something separated in time and space, and formed through analogy (comparison) or antithesis (contrast). Antiphrasis is an impressionistic expression to convey non-conventional meaning used for sarcasm. Build-forms or the constituents are given magniloquence by way of exaggerated scale, contrasts, precarious shape and intensive vibrancy.

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There are few features that rhetorize composite forms due to multiplicity of constituents elements. The sub-elements occur as microcosm, recurrence, as directional move, evolution-devolution and support-contrast. These rhetoric elements manifest in scaling, sequencing or within a perceptible domain of time or spatial reference.

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Design objects like architecture, fashion, products, are created for stake-holders and for personal gratification. Objects for personal gratification often result from intense desire to go out of the box as a non-conformal creative activity. This attitude, though very radical, resulting into unusual approaches and solutions, is tied to reality. All worldly creations are governed by factors like gravity, terrain and environment. Arguments of persuasion, justification or acceptance.

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Out of the Box thinking: It is believed, the term for unconventional perspective in thinking, has come from British mathematician Henry Ernest Dudeney. In this, nine dots are to be interconnected by using four lines drawn without the pencil leaving the paper. The puzzle required one to go beyond the dot array boundaries that is move out of the box.

9Dot puzzle

This is the 16 th article of 20 topics series on ISSUES for DESIGN

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MEANING of CRAFTS -5 -TOOLS

Post 651 -by Gautam Shah

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Tools are implements used by a person in manual operations for production or processing, like manipulation materials, craft-work, building construction, cultivation, food processing, offense-defence, handling, carriage, measurement and expression (writing, drawing, enacting). Tools have been used for making better tools. Tools are for doings things in an easier manner, as well as for doings things that otherwise would not have been possible by hands. There are few conditions where instead of the tools, the supports and other facilitatory structures and arrangements help in creative efforts and productivity.

Stone Age Caveman Ancestor Hunting Neanderthal

Tools are universal implements, used over different tasks and materials. Over a time, though, an exclusive manner of handling develops. The manner of handling evolves a holding mechanism. The holding mechanism, an entity integral with the tool, allowed efficient use of the tool. The combination of a tool and its handling mechanism was a task (and material) specific facility. The tools and handling section, each served different purposes, and so were shaped accordingly. Both faced different stresses and required different composition. But a combination of diverse forms and materials need to be compatible, coordinated and well joined.

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Handled tools extend and modify the reach of the body. The extended reach helps remote access, adds to leverage and allows torque or twisting. For cutting, breaking, beating, copping and such other jobs need leverage for impact or percussive forces.

Stone Age Tomahawk Blue Archaic Close Hoe Sky

A lever amplifies an input force to provide a greater output force. The lever arm is defined as the perpendicular distance from the axis of rotation to the line of action of the force.

Recognizing objects that can work more efficiently was the first craft. Refining by reshaping natural objects for a specific purpose has been one of the oldest craft industries. Some of the basic craft tools were for food preparation, and personal safety and security. Early tools were fragile and often got consumed in the use-processes. And so, the search for new tools was everlasting, alternatively new tools had to be fashioned from old ones. Redefining the tools necessitated search for better materials, sharpening the edge, and tying a handle.

640px-Adzes_from_New_GuineaTools were now of three basic classes: hand-held tools, percussive tools and projectiles. Other sub-classes were like cutting, scrapping, hole making, vessels, holding, measuring, coating-spreading, digging, mixing, etc.

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Primary tool materials were stones, woods, bones, clays and perhaps metals. Some of these could be re-formed by downsizing. Clay and metals were plastic materials that could be re-formed by moulding and additive process.

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Holding tools became important for two main purposes, to hold fine-sized objects and tools and to hold fire or hot things. Fine items like beads, and precious-stones need to be held properly to work upon them. Tool bits like fine and fragile edges need support, whereas fine points for drilling and engravings require adequate gripping. Tools were required to initiate, and work with fire. These included fire-fuel management utilities (chulhas), air blowers, handle for hot tools and holders for vessels. Agriculture related tools like thresher boards, winnowing baskets, sieves, land tillers, etc. Spinning, knitting, and weaving utilities developed for threads and cordage, which were used for binding handles, roof and wall elements, fishing nets, etc.

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Tools, as said earlier, are handy things. But there are many utilities, facilitatory structures and arrangements that have helped creative efforts and productivity. In these, at certain level of detail tools like appendages or similar advantages are invested. One of the first ones was the fireplace that contained the fire, helped efficient use of the fuel and offered resting stands for things to be heated. Similarly structures were created as dwelling spaces, clothes or apparel, shoes, head caps, adornments, toys, totems, murals, shutter systems over openings, hangers for food to protect it from insects and rodents, sleeping mats, hammocks and cradles, lamps that evolved less heat but more light, food grinding stones, narrow neck pitchers for liquid storage, slide for transporting goods, etc.

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At some level the tools, utilities, facilitatory structures and arrangements were merged as devices, machines, apparatuses, equipments or plants. These were integrated with the built-forms, for support, location-based advantage or task setting. The tool, craft and technology were one seamless pursuit. The pursuit also integrated several materials into not only single purpose entities but very specialized task facilities. The task related specializations also created technology-based castes, guilds and communities. The craft communities are tied to terrains and climates. This allows them to develop acutely ethnic styles.

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STYLING the ABSTRACT

Post 622 –by Gautam Shah

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Expression is main intention in fields like literature, art, architecture, fashion, and other branches of design. The expression has content that is implicit, subtle or explicit. Besides the content the expression emerges from a mix of medium and technique. The content as inspiration or realization depends on the intensity of personal relevance and comes in from many different fields. The medium and technique derive from many different geographies and eras.

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View of Gopuram (Gate Tower) Sri Mariamman Temple  Singapore > Wikipedia image by AngMoKio

The expression is sometimes made devoid of any content. But, one is never satisfied with the abstraction, and to achieve a better result it is tried over and over again. It results into an ‘abstract style’. The abstract style in absence of the content is strongly rooted with the medium and technique. Somewhere the ‘abstract’ begins to acquire a metaphoric meaning.

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Explicit expression TWA flight centre JFK Airport NYC > Wikipedia Flickr image by pheezy

‘Style is a characteristic or group of characteristics that we can identify as constant, recurring, or tenacious.’ + ‘Artistic style is the sum of constant, recurring or coherent traits identified with a certain individual or group.’ -Living With Art, Rita Gilbert

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Capriccio Palasttreppe > ART By Bernardo Bellotto 1721-1780

Such metaphoric content is matured by someone, but is invigorated by others in different time and space. And if the content, medium and techniques are different from the origins of inspiration, then ‘what is that‘ –Style or the Manner are reassessed. If style is holistic concept consisting of several characteristics, accepted and practised coherently by several persons across different fields of expressions, than Manner is a set of selected components that substantively codifies the ‘stylized expression’. Styles are creations that are distanced in locations and occasions, but with some re-collective connection. A stylized expression may not have cogency to the original. It is the mental image or glory that becomes the manner.

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Dragon gate at Guell Pavilions by Gaudi

Manners or ‘stylistic elements often reflect a period, a socio-political-economic environment. The scrutiny of the expressed forms into lines or shapes, frontal or angular views, foreground or background, the tempo, sensorial aberrations, colour or tonal gradations, etc. is imprecise. So manner criticism relies more on discreet terms to connote restrained, evasive reasonableness. A ‘manner’ is full of cramped codes, with silly and arbitrary rules.

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Atlantis supporting the balcony Tyszkiewicz-Potocki palace Warsaw > Wikipedia image by Bartosz MORAG

‘Mannerism, derived from the Italian maniera (manner) is a specific phase of the general Renaissance style, but manner is used very widely.’ Manner derives from Anglo-French manere, > Old French maniere > from Vulgar Latin *manaria (Spanish-manera, Portuguese-maneira, Italian-maniera, Dutch-manier, German-manier, Swedish-maner), > from fem. of Latin manuarius (belonging to the hand), from manus ‘hand’.

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Wassily Chair (Model 3B) designed by Marcel Breuer in 1925-26 at Bauhaus > Wikipedia image by Lorkan (Flickr)

Style and Manner both need, time and process to spread and sink into the society. The process of spread was accelerated manifold during the industrial age, due to faster means of travel and communications. The styles and manners, however, were recognized, and equally rapidly forgotten. These though incarnated themselves in other fields.

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Wall mural on singers of seventies > Wikipedia image by Alain Bertrand

Cubism remained with painting, sculpture and architecture and has not found expression elsewhere. Deconstructivism of literature by Derrida did not come to architecture till means of realization like CAD tools were available. Sensualism, psychedelic arts and make-believe in the cinema and graphics, are expressions still tied to the passage of time. Perhaps some different techniques of expression and realization are due. The concept of minimalism and sustainability may converge, and manifest as architecture of thinness and gravity defying stances. Compared with this literature is protuberant, still relying on elaboration and on metaphor.

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Luxor temple Egypt > Cartouches for Ramesses II > Wikipedia image by Asta

In fields like art, sculpture, architecture, fashion and other branches of design, which rely on expression through use of material and technology, changes in physical sciences are going to be the driving forces. In other fields of expressions like literature, performing arts, communications, the changes in behavioural and biological sciences will re-define the perception mechanism of the content.

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Story telling > ART by Albrecht Anker 1884

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UNDERSTANDING LACQUERS

Post 498 –by Gautam Shah

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Cosmetic Box

In early 1920 Lacquers were considered industrial coatings, mainly used by White-goods and Automotive industry. Earlier to this period a Lac or Shellac coatings were wood craft finishing techniques and material. Industrial age lacquers were favoured due to their fast drying and non-yellowing properties. Clear Lacquers were increasingly replacing tin as MS sheet coating for food packing but were found suitable for aluminium sheets packing such as collapsible tubes and canisters. Lacquers were also used for the nail polishes and as hair fixing sprays. These lacquers as the name suggests were not made of natural Lac or shellac but from Nitro Cellulose. The lacquers needed thinners of various types for different application technologies and seasons.

Lacquer Paint Pic from Wikipedia by Author Victorgrigas

Oil paints based on Alkyd resins or GP Enamels need thinner of single solvent material such as Genuine turpentine, Mineral turpentine and in few instance Naphtha or superior grades of kerosene would work. These solvents singly can work for all application needs and for cleaning-washing post-painting work. With alkyd-based paints, a resin is the film-forming component. It is reduced in viscosity during the manufacturing and later during application. The requirements of solvent-s differ according to ‘length of the resin’ (which designates the proportion of oil versus other modifying-polymerizing agents, such as typically a phthalic anhydride). Short-oil length resins may require stronger solvents. A solvent that dilutes the viscosity alone may not achieve application level of viscosity. Some type carrier or diluent solvents are required which acting as a ‘carrier’ material help achieves application level (such as spraying) viscosity. The carrier solvents evaporate fast before the chain linking (and so film forming-drying) process starts at ambient temperature, raised or baking temperature or through a catalyst enabled reaction.

Wood Brushing Lacquer Pic from Wikipedia Pic by Author Mk2010

The word Lacquer has become a misnomer. A Lacquer in nominal usage means a coating system that is fast drying, tougher and non-yellowing. All lacquers, however, are not NC (nitro-cellulose) lacquers. Other Lacquer coating systems formulations are based on Acrylic resins, Amino resins, Urethane and epoxy systems. NC lacquer dries with evaporation of solvents, at ambient temperature or often in warm chambers. Other formulations require baking-stoving environments or have two-pack system (a catalyst and paint mixed just before application). A NC lacquer film can be wetted-dissolved after drying (such as Nail-polishes of pre 1965 era) by a thinner, and are called ‘non-convertible systems’ (product that does not get chemically converted into something else). But newer generation-lacquers cannot be dissolved or removed easily after drying, and are called ‘convertible systems’ (product that gets chemically converted into something different).

Box Lacquered

Lacquer Nail Polish Pic through Wikipedia -Source http://www.flickr.com/photos/zitona/4733601645/ by Author » Zitona «

All types of Lacquers, convertible or non-convertible products require very specific type of thinner. A company that formulates the paint system, for reasons of Patent knowledge, may not reveal the exact formulation. So it is very necessary to use the thinner specified by the manufacturer. A thinner is a combination of different solvents. There are two important considerations, action of dissolving and diluting (acting as a carrier), and evaporation rates of the solvents. A Lacquer system may need as much as 75% or more thinners for spray like application. But after the deposition on the surface, it does not require such low viscosity. So some solvents (usually diluent or carrier) begin to evaporate very quickly. Some other slower evaporating solvents, allow time for film to level out.

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Lacquer coated Brass

A lacquer-thinner is a combination of solvents of basic Five groups. First group consists of latent solvents like Toluene, xylene and naphtha. The other three groups are of active solvents such as, ketones, esters, glycol ethers. Alcohol, though a latent solvent, in combination with other solvents plays an active role.

Lacquer thinners are affected by the weather and process of application. A normal thinner works for average temperature-moisture conditions. For very wet, windy weather and for brushing or manual polishing with a cloth bundle, reduced the rate of evaporation achieved by adding or using a ‘retarder thinner’. For spray like application, an accelerated rate of drying is possible and for this accelerator or fast lacquer thinners are used. Spray applications require more and faster drying thinner compared to wood lacquers that require less and slow drying thinner.

Channapatna-toys

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Shellac finishes were the first true clear coatings. Shellac is an insect exudate known as stick lac. Stick-Lac is refined to remove impurities and lighten its colour. Button-Lac is a manually purified is of darker colour, while machine purified shellac is often dewaxed and de-colourized. Shellac is soluble in methylated spirit or alcohols. Sankheda furniture and Chinese lacquer items are examples of shellac coatings. Shellac is a very effective coating material even in very thin viscosity, as a result its penetration and filling capacity is excellent. It is eminently recoatable so a very level and glossy surface is possible.

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COPPER -1

Post 477 –by Gautam Shah

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Pure copper nodule 40 mm across

Copper resources of the world are estimated at nearly 5.8 trillion pounds. Of these only about 0.7 trillion pounds have been mined to date. The recycling and recovery rates of copper are so high that of nearly all of the copper mined throughout history, is still in circulation today. This means nearly 80 % of all copper ever mined is still in use today.

Malachite, Zaire> Uploaded by JJ Harrison

Copper was discovered by prehistoric man, in search of shiny stones that when beaten did not break down but rather flattened out. This was sensational discovery leading to search of shiny nodules across lands. Pure Gold and Copper nodules were forged into items of adornments and tools. It was known that several nodules of such pure metals could be forged to form a larger piece. Such nodule findings were rare. But two forms of copper carbonates greenish malachite and bluish azurite were easy to identify and collect from the grounds. Malachite was also used as a gemstone. Similarly many other bright minerals were identified.

Neoclassical vase in malachite in the Hermitage Museum, St Petersburg Uploaded by Dezidor

Azurite 80 x 60 mm Azuritechessy.jpg Uploaded by Archaeodontosaurus

Copper was known around 10000 BC or even earlier. Earliest copper object, a pendant dating 8700 BC, was found Iraq. Copper, in natural nodules form, remained a prized material for a while, but soon became a metal of utility. Unalloyed copper is soft for tools and weapons, but fairly suitable for shaping of utensils. Mesopotamia and Egypt exploited copper for creating tools used in farming, wood working, cooking, etc. These were hoes, adzes, saws, combs , pots, dishes, chisels, harpoons, cloak-pins etc. By 6000 BC it was realized that, although copper was not amenable to casting, it could be worked by hammering, chasing, engraving, and cold-rolling. Sumerians used copper sheets to form sculptures over wooden forms and fastened on walls with copper nails or wires set in bitumen.

Imdugud (also Zu or Anzu), the lion-headed eagle; Sumerian metalwork (sheets of copper), Temple of Ninhursag at Tell al-‘Ubaid; ca. 2500 BC

The Roman supply of copper almost entirely came from Cyprus, and so was known as metal of Cyprus, shortened to cyprium, later corrupted to cuprum. Copper is found at many locations as a primary mineral in basaltic lavas and also as reduced form of copper compounds. It occurs in combination with many minerals, such as chalcocite, chalcopyrite, bornite, cuprite, malachite, and azurite. It is an extremely ductile and malleable metal with high tensile strength. It is an excellent conductor of heat and electric. It is a very noble metal and by acting as a cathode can corrode other contagious metals except stainless steel. It is resistant to most acids and sea water.

Bronze decoration

A Copper alloy with tin is known as bronze. Bronze is a stronger alloy, and harder than both the pure metals. Bronze can be cast. A copper with zinc is called Brass. It was also known that by hammering the copper became hardened, ideal for creation hard edged tools. Copper and its alloys, bronze and brass, mark the first science revolution of man. However, relative scarcity of tin in many regions of the world did not allow use Bronze equally everywhere. Tin-based bronzes were preferred due to the hazard of arsenic poisoning from fumes produced by the oxidation of arsenic-containing minerals. Copper-arsenic alloys, of superior properties to copper in both cast and wrought form, were produced in many regions. Arsenic contents varied from 1 to 7 percent, with up to 3 percent tin. In many civilizations the production of pure copper, arsenical copper, and tin bronze continued together for some time.

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STONE CRAFT

Post 464 –by Gautam Shah

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Stone craft consists of many distinct trades, like quarrying, handling-transporting, sizing, cutting, dressing, finishing and masonry work. The first stone craft was using the stone to make tools for working with materials. A right choice of stone quality and appropriate size-shape were important then, and continue to be so today.

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Stone is used for many different purposes.

  1. as industrial raw materials for minerals,
  2. as a constituent material in various composites,
  3. in buildings, for masonry, flooring and applique work,
  4. as an art and craft material.

Paulnabrone

Strength of a stone is checked for following types of stresses:

Compressive stresses, tend to decrease the volume of the material, causing breaks with a shattering effect.

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Tensile stresses, produce cracks and fissures, and torsion (or twisting). Generally, fine-grained rocks are stronger than coarse grained. Rocks with interlocking between the crystals are stronger than rocks with poor interlocking. Stratified rocks have poor strength along the plane or strata. Stratified rocks as a rule have lower strength than igneous and non-stratified homogeneous rocks.

Shear stresses, which move one part of a stone with respect to another, under certain conditions, inducing a permanent change of shape. These are best avoided by appropriate angle of extraction and cut, by careful orientation during coursing a masonry.

Cracks_at_Sunrise-on-Sea,_Eastern_Cape

Torsional stresses are important for structures of stones such as piers. Heat induced stresses were once critical for structures like fire places and hearths, but optional materials have obviated that as the criteria of design.

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The general requirements for stones used in Buildings can be summarized as follows:

■ Sound, uniform rock material.

■ Presence of rifts to facilitate workability by hand tools.

■ Porosity advantageous for cementing, provided it does not decrease the resistance to weathering.

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■ Inherent chemical stability to prevent fluorescence.

■ High strength (as required in certain cases).

■ Low specific gravity (necessary for easier handling and in light weight structures).

■ High abrasion resistance (an important factor for flooring, steps).

Palazzo dei diamanti, facciata principale. Wikipedia Image by Nicolò Musmeci

Masonry walls of stones require specific methods of construction such as:

1 Heaviest and thickest of pieces should be used for lower courses.

2 Small pieces of stones should not be used on outer face.

3 Best flat face with a smallest area should form the wall face.

4 Each stone must rest on a flat surface, if required flat face should be achieved preferably by dressing of the stone, by bedding material or mortar, or by use of splinters and wedges.

5 Wedges should be placed with their wider face on the inside and narrower face on the outside.

6 All loose particles, cleavages, layers should be removed before using a stone.

7 Joints must be staggered.

Palais du Luxembourg Bossage

8 In case of very thick walls, if more than two stones form a width, several full width stone should be employed for keying.

9 For all walls especially random masonry, the corners should be made of long rectangular stones of even thickness (preferably dressed).

Opus Reticulatum Pompeii Roman stone facing pattern Wikipedia Image by Jensens

10 Stratified stone materials should be used for compressive loads to occur across the section or strata.

11 For tension bearing areas stratified and sedimentary stone material should be avoided.

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