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

1280px-Sankheda_furnitureChairs_of_3_piece_set

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.

Sjb_whiskey_still

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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.

640px-Canto_tallado_2-Guelmim-Es_Semara

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.

640px-Roman_era_stone_arch_bridge,_Ticino,_Switzerland

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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640px-Lanzarote_-_stones_of_a_wall_-_pumice_stone

■ 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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WEIGHTING or BODYING OF TEXTILES

Post 447 -Gautam Shah

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Fibres, yarns and fabrics have poor bulk, or have lost bulk during various treatments are re-bodied by many different substances. Bodying is also possible without any substantive coating. Certain heat and water treatments shrink the fabric, increasing the bulk.

Starched sized Neck Cloth

Weighting or bodying is a fabric finishing process that may be applied at fiber, yarn or fabric stage. Users oriented bodying processes mostly occur after the fabric production, at clothes stage. One of the oldest known weighting materials has been the size. Starch, gums and gelatine have been used to size fabrics for stiffness, glaze and adding weight. Wool, jute, linen and such coarse fiber fabrics do not require weighting. Fabrics of cotton and silk, in fresh state, and used (after some wear) state need bodying.

Anna Pavlova in Giselle, wearing a romantic Tutu

Classical bell tutus in The Dance Class by Edgar Degas, 1874

Traditional sizing treatments are temporary. Modern day chemicals such as modified starch, polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC), and acrylic co-polymers provide long-lasting effect. Sizing of the warp yarn is required to reduce breakage of the yarn during weaving.

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1890s wedding dress made from weighted silk. The splits and damage visible on the sleeve are caused by the weighting process of the fabric.

Raw silk contains from 25 to 30 % of its weight in sericin or gum. When the fiber is cleaned or fabrics are washed, this substance is removed. Silks are weighted to recoup the loss in fiber weight, and to add greater body to fabric. Silk has an affinity for several metallic salts, like iron, lead, and tin. The weight lost in the de-gumming process is refurbished by soaking the fibre or fabric in a bath of the metallic salts. For freshly woven silk fabric, it is first placed in an acid solution of stannic chloride (a chloride of tin). After the absorption of the substance, the fabric is washed, placed into a solution of sodium phosphate and washed. During this process, an insoluble compound (tin phosphate) is formed. This adds weight and body. Sometimes further treatment with sodium silicate is done. A silk can hold considerably more than its own weight, though heavy weighting reduces abrasion resistance, leading to greater wear and tear. Weavers and merchants, once added 10 times more weight, then the customary processing loss of 20 %. One simple way to check presence of chemical weighting compounds is to burn a piece of silk fabric, and it leaves behind a perceptible skeleton of metallic compound.

Laundry Starch

Cotton and other materials are sized for very temporary to permanent treatments. This may be in the form of starch, gelatin, or resin or a combination of these with lubricating substances such as oils or wax. Starches and gelatin are temporary sizes and are removed during laundering. Cheap cotton or rayon fabrics are often heavily starched for stiffness which after laundering may become quite limp. Fabrics like organdy are permanently stiffened Cottons.

Starch Weighted head scarf

Wool fabrics are not weighted, but compacted or fulled to give the fabric more compact or denser structure. Melton cloth is very heavily fulled wool fabric, with a dense -felt like texture.

Melton Wool

Silk Sizing

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ART COATINGS

Post 432 – by Gautam Shah

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Lascaux2

Coatings are thin surface finishing techniques. A thin film is achieved by using a material that is in a liquid state or is convertible into a liquid phase. A coating may or may not have a colourant, but on drying achieves various degrees of transparencies. Coatings are applied to entities to alter the appearance, improve the tangibility and to provide a protective cover. Historically, however, coatings have been used for illustration and decorative effects.

The discovery of mixing dishes suggests that liquid pigment mixed with fat was also used and smeared with the hand. The subtle tonal gradations of colour on animals painted in the Altamira and Lascaux caves appear to have been dabbed in two stages with fur pads, natural variations on the rock surface were exploited to create the effects of volume.

Sleeping_Antelope_Tin_Taghirt

The simplest way of marking cave walls was to make finger-traces in the soft layer of clay covering the rock. Lime stone walls were engraved and filled in with iron oxide (hematite, or ochre), or the black pigment as manganese or charcoal. These materials were usually available locally. Analyses of pigments, reveal the use of extenders such as talc or feldspar, to increase the bulk of pigments. It also shows traces of animal and plant oils, used for binding. The pigment in paste form was applied with fingers, and also tools like animal-hair brushes or crushed twigs. Lumps of pigment discovered on cave floors may have been used as crayons, but since they do not mark the rock well, they were more likely to be sources of powder. Colour was often sprayed, from the mouth or through a tube. A network of ladder, supports and scaffolding was used to reach the ceilings and upper portions of walls. Light was provided by hearths, or portable burning torches.

Abric_on_es_troben_les_pintures_d'art_llevantí_al_pla_de_Petracos

Primitive coatings were daubing of clays, minerals, charcoal, lamp blacks often mixed with mediums such as water, tallow, vegetable excretion and juices, urine, blood, bitumen. Binding mediums were employed to fix the mineral or colourant particles on the surface. Some of the binding mediums were evaporative and worked only as a `leveller’ for particulate matter. By 6000 BC, in China, calcined (fired) mixtures of inorganic compounds and organic pigments and binding mediums (vehicles) were prepared from gum arabic, egg white, gelatin, and beeswax.

Some oily mediums though superior in fixing and longer lasting, but collected dust on aging. Oil mediums became darker in colour due to oxidation, or just peeled off. Some of the mediums were destroyed due to fungus and algae. Later little more complex substances such as starches of rice and maize, pine wood extracts, egg albumin, bees wax, hydrated limes, gypsum, etc. were used.

PREHISTORIC ART FORMS

There are basic TWO sets of Arts. Fixed arts are built-forms, wall murals and architectural embellishments. These could have been part of either exterior and interior environments. Portable arts, comprise of objects or artefacts. These usually remained in protected environments. Fixed arts were largely painted and scratched or engraved, but portable arts had, at least in initial periods, natural finishes by way of selection and production processes.

Venus_vom_Hohlen_Fels_Original_frontal

Portable arts consist of wide variety of object forms and material combinations. Compared to the fixed Arts the objects are smaller in size. The portable objects show all, the surface treatments, embellishments and coating applications. The objects of this category show greater integration of all the three interventions and greater detail or involvement. Large number and wide variety of objects have been preserved and recovered even from regions where Fixed Arts entities have not survived. Portable arts’ objects are smaller and personal hobby or a family craft creation. The colour and surface quality were matter of choice or discoveries through innovation in production.

Paulnabrone

Fixed Arts entities that have survived are surface treatments or renderings through show painting, scratching, engraving and daubing methods. On the other hand, the surviving built-forms, if considered as art-forms, represent technological milestones of material handling, supporting and construction planning. Fixed arts were large scale or important societal activities, involving entire community by way of voluntary participation or forced labour. The involvement of the community was for seasonal or occasional rituals. The leader, conductor or priest of the ritual and the team were the select few experts who initiated and updated the (art) entities over and over again. Such art-forms indicate occupation or interventions of several generations, as much as for more than 300 years.

Bradshaw rock paintings

Portable Art objects are incidental that is the availability, shape, size, colours, texture, etc. define the range of treatments. Many times the purpose it will serve evolves during the process of treatments. Such objects show material combinations. many different finishes were achieved, by change of forms and exploiting the tools. Material processes like heating, singeing, sintering, baking, beating, shaping, cutting, chopping, grinding, drilling, etc., were also used in farming and cooking. It was one seamless manner of learning.

Venus_of_Brassempouy

The materials were stones, precious stones, metal nodules, mineral and other colourants, woods, grasses, twigs, hides, leathers, skins, furs, hairs, shells, teeth, horns, bones, ivory, raw clay objects, baked clay ceramics, seeds, fruits, etc.

The objects formed were totems, body adornments, tools, implements, ritual and burial objects, cooking utilities, toys for children, amenities and dwelling embellishments.

Collier_de_Penne

These were exchanged, gifted to others or offered in rituals. The objects began to have consistent expressions. The varied metaphors, passing from one generation to other, ultimately became abstract. Coins, plaques, seals, etc. represent multiple conversions of expressions like a language.

Ggantija_Temples,_Xaghra,_Gozo

Fixed Art objects like built-forms, though functional utilities were built for community and for political purposes.

The public use entities were irrigation facilities, forest clearance, dykes, bridges, walks or passages, drinking water resources, community surround structures, security amenities and storage arrangements. These were not ‘decorative arts’ but symbolized technological innovations. Some like burial stones and dolmen had items of personalization.

Cave_Paintings_Bhembetika_(22)e

Fixed Arts objects like wall arts show skills of surface preparation, rendering or painting and surface finishing. These creations also show art of surface preparation by way of grinding, etching, daubing, engraving and colourant application. Wall-arts exist in odd narrow corners, at very high elevations, tall ceilings, day time dark corners and in nearly inaccessible places. The effort must have required support structures, bridges, scaffolds, illumination and ancillary works to protect the creations from moisture.

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MUD ARCHITECTURE

Post 426 – by Gautam Shah 

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9 Koyama_3

Architecture and structures of mud or clay, for every conceivable purpose, exist in all parts of the world. In hilly regions of the world clay sediments have been used for packing the joint and as a masonry course leveller. Mud or clay is used because of the abundant supply, near zero cost of procurement, wet plasticity, mould-ability, insulating qualities, high thermal capacity, non toxicity, ecological friendly nature and simplicity of application. Mud as a forming material for architecture, structures or ceramics have some drawbacks like, shrinkages on drying, i.e., cracking, poor weathering qualities, lack of homogeneity in dry state, high water permeability -hygroscopic, poor bonding to a substrate -peel off, vulnerability to white ants and insects.

Mud_houses_are_commonly_found_in_various_regions_of_Afghanistan.

Mud has seen renewed interest during the last Six to Seven decades. First interest in architecture was for its abundance and simplistic technology. Later, the material was favoured for its insulative qualities. During the last 4o years the mud buildings are being favoured for their Eco-friendliness, chiefly the recycle-ability aspect of it. The ideology of sustainability, with its varied interpretations, has supported experimentation for different uses.

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8 Berber village Near Ait Benhaddou 5600152155_532c99cc67_z

Some basic techniques of Mud construction are identified. These are: Sod, Rammed earth, Cob (cobb or clom), Adobe, Wattle and daub Compressed earth block methods. These techniques differ in details, from region to region, type of soils, natural moisture content and availability of additional water, additives, reinforcements and support form-work within reach. The mix design and forming techniques also depend on building elements (wall, slab, etc.), architectural elements and surface finish or applique decorations.

11 st_stephens_church_at_acoma_pueblo1

Mud architecture presents fascinating forms. The quality of space formation, the suitability for range of basic architectonic elements, adaptability to different usages, and the universal availability, make mud a very coveted material. The love affair is very poignant during the academic period of designers. The passion, however, gets muted over the years, for variety of reasons, such as lack of the clientele, the place, scope and sponsorship for experimentation and the irrelevance of the technology at locations where the educated designer will operate. There are many other reasons for a failed take off for ‘low technology and eco-friendly’ endeavours. Mud, is reckoned to be a sustainable material, of very relevant (‘green’) technology, non toxic, universally available and completely recyclable material.

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1 House_in_Toteil_002

These concepts remain valid so far as one can use the mud architecture concurrently with matching ‘lifestyle’ if one is conducting. A personal habitat of mud and to maintain (sustain) it for a long period, are two different things. A mud building is a very fragile entity and needs day to day care. Such concerns cannot be assigned to any outsider or agency. The cost of daily upkeep can turn out to be very high. And even if one can afford the cost, (which could be equal to the cost of a new structure), takes lots of time, practically a full time vocation.

7 Siwa mud Homes2009

Mud built-form cannot be conceived as a drawn plan or scheme. A person who constructs it must improvise it on own. The execution of such form cannot happen quickly, and during the period whatever that has been constructed will need updating and improvisation. Some of the key elements of built form, material behaviour, form and space organization exist in the society that has been using mud for generations. These innate capacities can be reinforced by being not only an active participant on the site, but by being an inhabitant of the entity. Only an inhabitant of the mud architecture can sustain it.

4 Mud_plaster_over_straw_bales_wallDesigners cannot, and must not meddle in mud architecture design or execution. A design student may be asked to design one and perhaps execute it, as a learning exercise. The fashionable word coined by teachers who never practice, or have never done, is “hand on experience” in material-form-and the technological implications.

3 Annual_repair_of_the_world's_largest_mud_brick_building_the_Great_Mosque_of_Djenné_in_Mali._(32088227574)

 

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DRAPERIES

Post 424 – by Gautam Shah

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Room_at_Nikoi_Island

A drape is a way of hanging or placing an unstitched piece of fabric. The word drape derives from Proto-Germanic drapiz and drepiz (=a strike, hit, blow), (=intended for striking, to be beaten), it also relates to English drub (=to beat) and Swedish dräpa (=to slay). In ancient periods a drape-able fabric was heavily (beaten) washed, and so soft and pliable. A heavily washed fabric is dull or of unbleached natural colour. At places a dull cloth is described to be greyish to yellowish or light olive brown in colour. The loss of crispiness perhaps indicates use of Linen, which became soft after several washes.

The word drapery is of 14th C origin, but drape or equivalent usages must be very ancient. Unstitched pieces of fabrics were used for covering own self by ordinary people as well as priests and rulers. The draped fabric, if soft, hangs loosely. The fabric, if stiff or of heavier weave remains fluffy, and does not ‘fall’ gracefully. The fabric worn as dress usually has vertical folds, which change with body movements. On a performance stage, it creates an impression of ‘larger than life movement’, perceptible to the spectators in the last tier of the Amphi theatre.

Theatre_actors,_Yuan_Dynasty

A_group_of_Lepchas_in_Darjeeling_(c._1880)

india-978488_640

Drapery refers to composition of fabric used for decorative purposes, around internal or external gaps or openings. It also means any arrangement of fabric used as clothing, backdrop, accompaniment or adornment for a work of art in the form of painting or sculpture. Each artist and each era shows unique techniques of rendering the drapery curves and form. The quality of fabric material never shown as actual, it only enhanced the form of drapery. The colour of the drapery as shown was the artists’ pallet requirement and may not be realistic. The transparency of fabric and body revelations were according to the artists daring and perhaps client’s dictates.

Gandharv Buddha 1-2nd C BC

Sarcophagus of the brothers 250 AD > Wikipedia Image > Farnese collection

Leonardo studies for draping

In interior Design all types of fabrics are used for draping the furniture, openings, gaps, parapets, railings, columns, brackets, steps and stairs. These are covered with many different grades of fabrics ranging from sheer silk, flimsy organza, sateen, damask, linen, velvet, starched cotton, and later rayon and polyesters. Drapery colour and pattern schemes were coordinated with wall papers, curtains, carpets and other tapestries. Fabrics have been hung with formation of gathers or unstitched pleats, of vertical, dropped or sagged curves and twisted horizontals. Tapestry like one-sided fabrics are also draped over architectural elements of buildings.

Portrait of Mrs Abington British Actress 1737-1815 ART by Joshua Reynolds

Draperies were inevitable part of beds and bedrooms. Bed was the most important chamber for the lady of the house, almost like a female drawing room. Beds were separated by draperies from the room space, and beds structures were covered with drapes. Back side of the bed had hung piece of tapestry fabric or some form of drape composition. Paintings and portraits were edged with draperies.

Reconstructed Royal Bed at Warsaw Castle Wikipedia Image by Giorgiomonteforti

Draped fabrics were great collectors of dust and soot. The shaped drapes if too articulated, fluffy and against the gravity, have a tendency to collapse. The drapes are generally static arrangement, but during the early part of 19th C began to be replaced by simpler curtains. The curtain required pelmets or open hanging rods, both of which began to be covered with scallops. Scallops are articulated drapes, with ropes and tassels. Word Draper is used to denote an expert tailor or an establishment that stocks various types of fabrics and paraphernalia items.

Scallops over curtain

In art forms draperies have been treated both casually and formally, with neatly delineated lines or free-flowing curves. This has depended on the person to be presented like, an angel, Lord, saints, or commoners. Hellenistic period art draping was white or light coloured translucent body touching, but form emphasizing fabric. Gothic period showed the restrained flow of lines. Post renaissances, the drapery presentation was theatrical. Drapery presentation in painting was such an important issue that it was first discussed with the sponsors. Specialist painters were hired to touch-up the drapery work.

576px-Melody_In_Marble,_Veiled_Rebecca_at_Salar_jung_Museum,_Hyderabad,_India

ART by Frans Hals 1625

Unstitched Appearals

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PRIMITIVE COATINGS # 1

Post 411 – by Gautam Shah

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Coatings have been used for decorating and suffusing objects and surfaces for the past 60000 years. These were used for several purposes such as to add a colour, impart a protective layer, ‘plaster’ a surface, imprint a pattern or create an identity signage.

Stone and other artefacts requiring coating or decoration

A primitive person had many objects that could receive the coatings. These objects were natural, reformed or produced ones. The objects had different sizes, shapes and surfaces. The surfaces had characteristic textures, porosities, base-colours and patterns (grains, patches, stains, etc.).

Korea Neolithic age pot

The objects were own body skins, hairs, and nails. Animal products like teeth, animal hides, furs, bones, and teeth. Minerals’ items like sands, clays, stones, rocks, precious stones, and sea shells. Plant items such as dry leaves, grasses, seeds, dried fruits, fibres and woods. The manufactured range of items included clay products, ceramics and metals.

sesklo

The surfaces were prepared to receive the coating. Hides were cleaned and shaved by heavy rubbing. Body surfaces were oiled to receive the colourants. Walls were washed and wetted prior to coating application. Bones were ground to remove the sheen and make surface slightly rough and absorbent. Stones and woods were polished or scrapped. Raw and baked clay products were re-fired after coating. Leaves were rolled and flattened and dehydrated at the green stage by burying in layers of ash or sand.

The coatings’ materials were of natural origins, such as available off the ground, or from animals and plants. But the coating materials were processed by filtering or sieving, washing, cleaning, decanting, boiling, singeing, and sintering.

The act of coating was intentional, done with a sure purpose. But the resultant effects were wondrous, something that gave a new purpose to the artefact. The art of drawing and the technique of coating, was seamless process of magic. A process to express, what the postures, gestures or spoken language could not do.

Coating techniques and materials of the primitive age are still being used in many situations, and so continue to be relevant. Blood is perhaps the earliest colourant, as a fresh liquid it has very rich colour. It was a colour to represent the vibrancy of life and metaphorical power over the kill. Blood, however, is biologically degradable material, dries to a darker shade, and has very weak colour-integrity. Wood coal is a dry colourant, easy to handle. It requires a textured base for ‘rubbing-in’ or a binding liquid to form an applicable paste. Carbon (Lamp) black -a deposition collected over burning fat or oil, is much better due to oil content. Whites were procured from metallic oxides and carbonates. Lime is most common everywhere. Other whites included talc, whiting and barytes. Iron oxides are equally common, and have many different hues (such as yellow ochres, browns of sienna and umber, red and black oxides). Oxides are very stable, and have ‘deep’ saturated colours.

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Black Carbon of Soot or Lamp black

In this palette of colours, the notable absence was Blue and Green. Blue and green appeared very late in the form of Lapis lazuli and Malachite (copper carbonate hydroxide). Brilliant Red that could represent the fresh blood, and Brilliant Pink of the meat were also absent. Purple was nearly unknown. The absentee colours were sourced from plant juices and natural dyes, but had poor colouring strength or low opacity (transparent), sun light fading, and biodegradable colours so were not long lasting.

Sprayed colours

The primitive colourants were mostly of dry powders or soft rocks. These had no binding capacity. Mineral pigments were heavily rubbed on the surface to trap them in the micro cavities of the surface. Liquid juices could absorb into the surface. Some form of binding material or technology was needed. Water has temporary binding capacity and can be used as a carrier agent. To fix colours plant oils, mutton fats, fish oils, etc. waxes, and plant latexes were used. These substances except the wax were ‘non-drying’ and remained wet for a long time. The wet surface attracted dust and trapped insects. The oily substances biologically deteriorated, and on oxidation turned darker in colour.

Proteins-based materials like blood, eggs, milk, urine, and starches were also used as binding materials. Plant and insect exudates or natural gums had binding properties but were highly hygroscopic (affinity with water) materials. Plant milks or latexes, like materials, were also used. Wax was used to mix with pigments and as a protective layer. Wax and natural Creosote were used to protect wood and leather surfaces.

Number of cementing substances were used for coating or plastering. Mud plasters, slaked lime and Pozzolana (volcanic) ash, were materials that had binding properties. Colouring these substances, or coating over it (fresco style) required large quantities of materials, or concentrated pigments. Lime when mixed with a colourant imparted a white shade creating a ‘pale’ effect. Pozzolana had darker colour so made the colourant several shades darker. Plastering and daubing, were frequently used to prepare a better surface for a wall painting. Primitive binding materials can be categorized like, 1 Materials that are water reducible, water resistant and hygroscopic, 2 Air drying and non drying, 3 Non water-based materials.

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The primitive age craft of coating can be summed up as 1 Surface preparation, 2 Application of the coating, 3 Applying tonal variations or shades, and 4 Covering the surface with water protective coat, usually of oils or other transparent materials. The process of application of colourants or the coating system was adapted to the nature of the base surface, as much as to the type of colourants and binders.

Twig brushes

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Drawing points and crude shading brushes

Primitive coating applications are varied. The simplest way of marking cave walls art was to make finger-nail traces in the soft layer of clay covering the rock. Lime stone walls were engraved and filled in with iron oxide (Hematite, or ochre), or the black pigment such as the manganese or charcoal. Analysis of cave wall art pigments, reveal the use of extenders (dull or low opacity powders) such as talc or feldspar, to increase the bulk of pigments. The coating also shows traces of animal and plant oils, used either for binding or as a protective covering. The pigment in paste form was applied with fingers, and also tools like fiber pads, animal-hair brushes or crushed twigs. Lumps of pigment discovered on the floor of caves were perhaps used as crayons, or were grinding onto colour powder. Colours were often sprayed, from the mouth or through a tube. A network of ladder, supports and scaffolding was used to reach the ceilings and upper portions of walls. Light was provided by hearths, or portable burning torches. The coated surfaces were ground to achieve a sheen on the surface or re-coated with a protective layer of egg-whites, oils or fats.

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The earliest known use of colourants dates back to 70000 years, whereas Cave wall art is about 40,000 years or older. BC. Lascaux, an underground cave, 17300 BC, located in SW France, has walls and ceilings, decorated with some 1,500 engravings and about 600 paintings in shades of yellow, red, brown, and black. The subtle tonal gradations of colour on animals painted in the Altamira and Lascaux caves appear to have been dabbed in two stages with fur pads, natural variations on the rock surface were exploited to create the effects of volume.

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SMITHY

Post 396 – by Gautam Shah 

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Smithy is a work-place where metals are worked by heating, casting, and hammering (forging) for quality modification, shaping and joining. Copper, bronze and silver were some of the first metals handled in workshops. Smithy is called a Forge. But bronze is not as malleable as copper or silver, and it was not readily forged or chased, but cast. Copper was shaped by forging. The traditions of metals like bronze and copper helped man to deal with cast iron –a castable metal, and little later wrought iron –a workable metal. The term to wrought derives from work.

typical smithy in Finland

A smithy is also called a forge, as hot shaping or forming is chief the activity here. The metal workshop processes are associated with hearth, a place to hammer, chisel, punch, shear bend a piece of iron, and water or oil for quenching the item.

Bassano_Forge_of_Vulcan

Metal pieces are heated to a temperature range at which work hardening does not happen. The heated metal piece is held with tongs and taken to the forge. Here the work-piece is held with tongs and other types of holders while forging. The heating and forging sequence is repeated several times, to maintain the temperature. The piece is than taken to a tub of water (or oil) for quenching or rapid cooling.

Iron Forge

Once upon a time forging workshops were independent units, owned by a smith and serving variety of needs of a neighbourhood. These needs were cooking vessels, plates, bowls, spikes, nails, cart axles, horse shoes, agricultural implements, tools, etc. Iron smiths were employed at construction sites to produce architectural entities such as lattices, screens, partitions, fences, stairs, balcony railings, horse appointments, weapons, posts, and building hardware, etc. ‘Locksmiths’ were fine crafts persons, with capacity to devise clocks, locks and other gadgets. Their ability was to rework a smithy item to finer details and embellish it with many different materials and techniques.

Blacksmith at work

Iron Smiths in later part of 18th C also began to work with rolled metal sheets, items such as trunks, cabinets, truck and other vehicles bodies, buckets, vessels, etc. These items of rolled metal sheets were cold-worked, and did not require any forging. Similarly Iron smiths began to be employed on construction work sites for cutting and rivetting rolled steel structural assemblies.

A smithy or forge has following tools and facilities. Some of these are now made from very superior materials and automated.

Hearth

A Hearth is a place where coal, charcoal or other fuels are burnt. It is designed to contain and control the fire by amount of air, volume of fuel, and shape of the flame or heat spread. The hearth is aided by a Tuyere (a pipe through which air is blown into fire) and Bellows or blower (for forcing air into the tuyere). Bellows were once made of leather, and blowers are fans moved manually or by power. The hearth fire is used for effecting metallurgical changes like hardening, annealing, and tempering, etc.

Working at Anvil

An anvil is a block on which forging is done. It is placed as very steady piece and used as a support for all metal manipulations. Its size and shape vary according to the weight of work piece and nature of operations. Most anvils have a wide base for stability, a body, a flatter main work face, projection called horn, and variety of edge forms, holes and depressions.

Tongs are used for holding, carrying and turning a hot metal piece. Tongs have similar mechanisms, that is long arms but variety of holder mouths. Vices are clamping devices mounted on work bench end.

Chisels are used for cutting and chipping, but separate for hot and cold work. Punches are like chisels but blunt edged for forming holes or depressions. A drift is a large sized wide cone punch used for enlarging punched holes.

Hammers for smithy

Hammers for smithy

Hammers are called a smith’s hand. Hammers have different weights of heads, types of head formations such as pean, eye, cheeks, face, and lengths of handles. A crafts person on own uses lighter to medium weight hammer as other hand is used for holding the iron piece in a tong, whereas an assistant uses both hand for a heavier sledge hammer. Nowadays power hammers are used.

Modern smithy have other facilities like lathes, drilling, shearing, punching machines, cutting saws, grinders and welding equipments.

This article on IRON SMITHY was published on my other Blog >>> http://talking-interior-design.blogspot.in/2014/11/iron-smithy-craft-1.html

STITCHING AND SEWING

Post 390 ⇒   by Gautam Shah

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tailor-shop-vintage-painting

Roadside_cobblers._Rekong_Peo

Stitching is mainly done on fibre, film or pliable laminar assemblies. Stitching is a continuous linear fastening system, compared to Knotting, which is of intermittent stitches. Machine Stitching is common to garments and bags packing (cement, grains). Machine stitching is done with two individual fibres, on either of the faces, so a fibre pull from the other face (from the machine) may undo the assembly. Hand stitching is used for garments repair (Rafu – darning work in India) and for preparing Razais (Indian blankets stuffed with cotton). It is done with a single fibre as a continuous stitch, and so is more stable, but not necessarily stronger. Knotting is very common in making of cotton mattresses. It is stable and stronger as each knot is tied separately, and even if one of it comes apart, does not affect the entire assembly.

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Different types Threads for Quality of Fabrics

Majority of stitches are made with a needle eyed at the end. Cobblers, sports goods manufacturers, and for heavy duty work a notched hook-needle is used to pull over a looped hung-thread. Complex stitches may employ one to four threads. There are several variations of stitch formations, such as, Running stitch, back stitch, looped stitch, edge seaming stitch, darning or Rafu work stitch, buttons hole stitch, etc.

Needles (for Hand sewing

Sewing awl

Stitching materials are threads of cotton, silk, rayons, polyester, Nylon (Aramid), stretched guts of animals like cats, spliced leather, metal wires and spliced stripes, (silver, gold, copper, aluminium). Stitching material must have strength equal or less than the material to be stitched. A stronger stitching thread cuts into the material being stitched.

Sewing Tools for Leather

Specific materials are used for joining two similar or dissimilar materials. Materials that are fragile (stitch cutting into the material), are stitched with extra resilient strips, on one or both faces.

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Quilting stitches

Surgeons use stitch materials made of animal guts (processed intestines of cats stretched into a fine thread) or fine quality nylon, polyesters and Teflon. Surgical stitching material must not biologically react with body. Dissoluble and de-gradable threads are also used in surgical procedures.

Knotting in Mattresses > Wikipedia image by Jeffrey M. Vinocur

hands-knitting-knitted-sweater

Fusible threads fuse to form a joint with the fabric, on post stitching heat or chemical treatment. Rafugars (Indian -fabric/garment darning) use very fine threads, or often single filament fibres to create a network of stitches (akin to weaving or knitting), to join torn sections and strengthen weakened areas. The filament is pulled out from the selvage of the fabric (or garment) to create a perfect colour match.

Glove Ball Baseball

Knotting is in many ways similar to stitching, but unlike the stitching it is not a continuous process. Knots are created intermittently or at the end of a ductile or flexible linear element like yarn, thread or a rope. Cross knots tie up an assembly, to join one linear unit to another, and Wraps keep unravelling loose ends of a thread or rope. Knotted wraps also do not let a rope or thread go-off, whereas Unknotted wraps are created by winding loose ends, or with the help of an extra thread or wire to form a smooth end that can easily slide through a whole, eyelet or sleeve.

Leather boot stitches

Elevator metal wire ropes’ ends are rolled over a circular section and secured together by a friction holder. Pre-stressed wires in RCC structures, wire rope bridges also use similar friction holders of conical shape.

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Lashes are straps or stripes cut from of leather, polypropylene like plastics, or malleable metals, or knitted or braided threads of round or flat section. Lashes are used for tying sails, tents, shoes’ uppers, paper, bamboos, canes, etc. with or without the use of eyelets. Straps are secured by buckles, knots, rivets or wraps. Metal lashes or straps of annealed mild steel are used for tying bales of cotton and bundles of fabrics. The ends are tied together by crimping a small piece of malleable metal or by riveting. Fodder grass bundles are tied using metal wires. Here ends are secured by knotting.

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