Tuesday, July 29, 2014


by Gautam Shah ➔ 

Sistine Chapel Art restoration
Buildings are affected by time, environment and human use. The buildings become increasingly inefficient and irrelevant with time. The environmental processes continue to change the fabric of the buildings. The human use, miss use and non-use, all reflects in the decline of the building. To terminate or arrest (decelerate) the affectations in buildings, several process of change are required.
The change-processes cannot revert a building to its original condition. The building loses its site related relevance and time related functionality over a period of time. This has vast context, and it is a long term cumulative change. It is not possible to re-establish a building, because 1. One cannot regress a building to a past state in isolation of its referential conditions, 2. Buildings are continuously altered nominally and intentionally, but the extent of such alterations not clearly layered or recorded, 3. The materials and technologies may not be available. 4. In most of the cases the value identity is metaphysical.

Restoration is reinstatement of a previous condition. A building or work of art consists of distinct components, some of which may have been created, included or changed at different times, or have been affected variously. Such changes, even if intentional are rarely sequential in time and space, or properly recorded. The evidence of previous condition is largely conjectural.
From ancient times down to the first quarter of the present century, restorations have always followed the sponsor’s needs and restorer’s wisdom. Restorations have meant all nature changes, such as renovations, alterations, reformations, additions, and extensions, but rarely ‘reinstatement of a previous condition’. ‘Restorations’ (that is all type of change) have been carried out by masters such as the professional artists, sculptors and builders and street level roving crafts persons. The nature of ‘change’ interventions depended on the skills of the master. Such changes were primarily intended to put building (or work of art-craft)to a better condition. It also meant ‘improvising or adapting a style or confirming to a contemporary taste’. Changes have moulded the entity into grandiose, to brand their capacity rather then any respect for the past. The restorer, Michelangelo or some crafts-person fashioned it into more elaborate. 
During Romanesque and Renaissance periods classical antiquity was regarded as something to be appreciated, but that was for the final result, not as a process. Medieval builders treated the works of antiquity as something to be extended. Abandoning substantial size of work meant creating equally large or better structure which would take more then a lifetime. Restoration was resurrecting a building with ‘change’. Gothic cathedrals were planned, started and on the way re-changed several times with the inclusion of the style of the day. Such a complex entity cannot be identified to a particular or ‘original character’.

With every change exercise, something of the original character was irretrievably lost. Too many such exercises ultimately diluted the original character of the building. Buildings are restored for their partial identities, like values, utilitarian aspects, sensuality, materials, technology, architectural character, spatial qualities, style, patterns, scale or proportions, antiquity. Partial restorations are comparatively easy as the retained identities seem to provide a link between the past and the present.
heatre of Marcellus
  • Theatre of Marcellus (Italian: Teatro di Marcello) in Rome, Italy, is a classic example of a building that has been changed by several owners over more then 2000 years. Site space for the theatre was cleared by Julius Caesar, but could not begin it. It was formally inaugurated in 12 BC. The theatre fell into disuse by 4th C and debris was used in other projects such as the bridge of Cestius. Statues, however, were restored by Petronius Maximus in 421 AD, and the remaining structure housed small residential buildings. During the 11th and 12th C AD it was converted into a fortress by the Pierleone family. In 1368 AD the Savelli family took it over, and in 1519 AD employed Baldassare Peruzzi to design a new building (palazzo) incorporating the ancient ruins. Further alterations were made in 1712 AD by the Orsini family and the building is now known as the Palazzo Orsini. The upper portion is now divided into multiple apartments, and its surroundings are used as a venue for small summer concerts.
Theatre of Marcellus -old sketch 

Tuesday, July 22, 2014


by Gautam Shah

Woods are fashioned to a variety of finishes such as bark stripped, chopped, rough hewn, sawn, planned, sanded, etc. Finish for a wood depends on several factors.
1. Type of wood -soft or hard
2. Quality of wood -jungle, commercial or special, etc.
3. Portion of wood -sap inclusive or heart exclusive
4. Type of cut -quarter, rift, tangential or slab etc.
5. Section of cut -along, across or askew to the grain
6. Anatomical peculiarities -straight or cross grain, knots, shakes, pith
7. Presence of chemicals -aliphatic compounds, waxy and resinous substances
8. Environmental conditions
9. Type of feel (texture) required
10. Type of look (grain, pattern) required
11. Economics -cost and maintenance
12. Time available for process
13. Tools and technology available
14. Age of wood
15. Moisture content of wood
16. Proposed use

■ Rough finishes are cheaper, take less time to prepare and require simple tools and techniques. Some rough surfaces give better bondage to preservatives and coatings. Rough surfaces are good for moisture movement but are highly vulnerable to insect and bacterial growth. Rough finishes hide local defects such as stains, knots, ugly grains, fine cracks etc

■ Smooth finishes are costly, require finer tools and superior techniques. Smooth finish often give poor bondage to preservatives and coatings but one requires much lesser quantity for coverage. Such finishes do not collect dirt. Smooth finishes discourage bacterial growth as do the rough finishes. The timbers for smooth finish should have a fine grain pattern. Heart portions are much better for smooth finish then sap portions. Sap portions may however, be finished fairly smooth, provided are immediately covered with moisture proof coating. Hardwoods usually provide smoother finish and of permanent type then soft woods. Woods with resinous or oily substances generally have a natural smooth feel, however, if the substances are reactive or soluble in water or aliphatic solvents, may create problems during coating. Sisam and Rosewoods have oily or waxy face, which does not allow oil paints or varnish finish. Such woods need to be covered with very thin coatings based on solvent evaporation drying, like nitro cellulose lacquer. Timbers surfaces are flame charred or singed to provide slightly darker to black tone to selected areas. The flame is either `cool' capable of depositing carbon or `hot' to singe the surface.

Valence Parquet Wikipedia Image by Morburre

■ Colour of wood shows a wide range of variation. The colour, of the same kind of timber changes depending upon whether the surface is freshly cut or has been exposed. Both sapwood and heartwood change colour due to slight oxidation on exposure. Some timbers do show certain characteristic colours. Sapwood is generally lighter in colour than heartwood. This distinction may be well defined as in Chir. Sissoo and Kokko or somewhat less well defined as in Sal and Haldu. Some timbers like spruce, fir, etc. show such colour distinction between heartwood and sapwood. The colour of wood may be uniform. mottled or streaked. The colour may vary from creamy white (Deodar, Birch) to jet black (ebony, mahogany) through varying shade of grey (oak), yellow (Haldu), pink (Lali, Pali), red (Walnut, Sisam), brown (Teak) and purple (Rosewood). In general, a darker colour in wood indicates greater durability because of the presence of natural toxic substances. 

■ Grain in timber refers to the general direction or alignment of wood cells. Depending on the actual alignment, the grain may be straight, spiral, interlocked, wavy or irregular. The nature of grain considerably affects the strength, seasoning and other properties of timber. Grain if not straight is a defect in timber. Straight grains usually occur in normally grown or in planned plantation trees. Particular type of grains many commonly are found in some species, like interlocked grain in Sal. Spiral grain is a natural defect due to the irregularities in the formation of the fibres themselves. This may make conversion difficult and also reduce the strength of timber. Timbers in which the grain changes direction to left and right more or less regularly have erratic grains. When radially cut this may produce beautiful figures and is useful for veneering. Wavy grain is produced by undulations in the wood. This weakens the timber, but many times it is valuable for the beautiful figure on the cut surface.

 ■ Texture of a timber depends on the size and variation of cells, dimensions of vessels and the width and abundance of rays. Timbers with large vessels and broad rays have coarse texture. Trees growing in favourable conditions and having faster growth has larger cells and is less compact than trees growing in a difficult terrain and adverse climate. Softwoods have marked variation in rings due to severe seasonal climatic alterations, and consequently on drying show uneven texture. Softwoods generally have fine feel due to presence of resinous substances. A moist wood, if planned has coarse texture, due to the rise or uprooting of fibres on further evaporation. Similarly an old timber which is very dry tends to be brittle at edges. A fresh wood may provide smooth feel due to the presence of oils, waxes and moisture, compared to an old wood which may feel dry and less smooth due to micro pores on the surface

■ Performance of a timber is measured in terms of its strength, durability, stiffness, toughness, colour, texture, size, availability, weight and moisture characteristics. Timber has certain disadvantages in comparison with other structural materials. Its size is limited to the width of a tree trunk. Quality is rarely uniform even within a section. It is susceptible to decay. Its greatest strength lies in the longitudinal direction that is along the grain, whereas it is comparatively weak across the grain. Though some wood show excellent shear resistance across grain. Fast-growing trees which can provide an easy renewable source of supply provide timber of poor structural or aesthetic qualities. A substantial part of a tree is lost in making timber for appropriate use. 

Wednesday, July 16, 2014


by Gautam Shah

Selling a commodity or providing a service has been basically a street level business. It needs ‘commercial architecture’ to facilitate it. The seller or provider and the customer depend on prior visual recognition and confirmation. Shop Windows, Shop Fronts or Display Windows are the architectural elements for visual recognition. The architectural character of it is highly climate dependent and very slightly affected by the culture of the place.

The shop-fronts of tropical and colder climates show distinctive difference. The tropical shop was an entirely open front unit compared to the ‘shop-windows’ of colder climates. The later, were small but regular openings, like a glazed section within a door or window. Of course between the two climate-based extremes there were many intermediate approaches to shop-fronts.

The tropical shop attended the customers at the street edge, and had the entire shallow depth frontage for display. On the other hand the colder climate shop was enclosed space. It managed its business deep inside with a much larger volumetric space for display.

The shop windows made a street lively and began to endow a unique architectural identity to the shops. Different trades, like barber, tailors, butcher, sweets, bakery, fortune tellers, medics, each had unique interior space character and their shop fronts reflected that on the street. In warmer climates shops, the interior and exterior of the shop were one.

The shop window or front constituted the ‘display system of the business. It was also a manner for typecasting or branding the nature of the business.

Shops along a street tend to be nearly of the same sizes and architectural character. It requires professional design help to be a distinctive entity. But to arrange and rearrange the merchandise visible from the shop-front or shop-window was within the ambit of the owner. These also included festival signages, colour schemas, illumination, all called window dressing’.

Shop fronts were, once not regulated by any building authorities. So upper floors were extended to protect the shop front area. Such unregulated projections often extended to the edge of the footpath, and required support of columns. Over a period entire street had a continuously protected passage like a colonnade, similar to one designed colonnade in Connaught Place at New Delhi. However, later rules did not permit more than 11 inches of projected cover. These very small provision was used for shaping the shop window like a bay or bow window.

Shop and dwelling architecture had very little scope for undulating the face. Pilasters and Consoles were used to add a strong edge and a separating feature for the shop front. It also enhanced the shop-front within the building elevation. Fascias and Cornices were other elements incorporated with the shop face. A cornice was purely a decorative element above the fascia, or was used as cover for retractable blinds, folding awning or roller shutters.

Old shops-fronts were raised off the road level and also from the shop interior floor level, by means of a stall-riser. The stall risers provided a higher base to display merchandise and protected the shop-window from ramming by the cyclists.

Shop + dwelling, or workshop+dwelling have been the most convenient combination everywhere in the world. The arrangements were of front shop and backside dwelling, or ground floor shop and upper floor residence. With development of exclusive commercial precincts, the lower floors of office buildings were devoted to shops. The upper floor shops had a street side ‘frontage’ for display and backside entrances.

Early Display windows were on the public street level. A customer looked at the displayed items, and in few cases whole or part of the interior, at a nominal eye level. Shops on the upper floors or down at cellar level, offered a different perspective which required a different arrangement. At whatever level the street facing display was extremely important, but occupied a lot of floor space. Display systems were made visible not only from outside, but from inside the shop, to endow double efficiency. Such dual faced display systems also allowed greater view of the shop interior from outside.

Boutiques, parlours and showrooms used the entire interior volume of the shop as a display set-up. Interior display units were very useful to showcase precious (jewellery) and easily perishable (food stuffs) items. Large departmental stores required exclusive interior display units.

Exclusive display units or cubes with no attached selling facilities began to flourish on heavy public access routes such as railway and bus depots. Such display cubes had premium rents and with too little space for display, so graphical images rather then actual items were placed.


Early shop-fronts used glass on a very limited scale. The door (as enlarged peep hole) and windows (with chequered panes) formed the window-front. The glasses were of smaller units for THREE different reasons: technological, economics and safety. The glass in the door or window could only be enlarged to the extent of the frame. The small window just gave confirmation that shop is open for business, a glimpse of the business inside, and also an assurance to female customers that the shop is transparent and so safe. For the vision inside, the shop had to be brightly lit even during the day time. In small localities where the nature of a shop is familiar to everyone in the neighbourhood, display may not be important to attract a customer, but a display system for new arrivals or preparations was necessary.

Glass became a shop-front factor in warm climates when shops needed environmental control such as heat, dust, rain and noise. Privacy was an important factor for some businesses, and ground glass partitions helped it. But these were not display fronts.

Early shop doors were of half glass+half wood panelling, or full glass+ bottom feet’s knocker plate. The doors had engraved name and logo of the shop. The doors were floor pivoted, so opened both ways. Shop-window became large but initially with mullions divided glasses. The stall risers began to be eliminated.

The display section covered the entire frontage of the shop except two major obstructing elements, the entry door for the shop section, and another door for the residential quarter on the upper floor. The shop door was set back to provide a protected entrance bay, and front opening of the shutter. It also allowed the shop front to form a bay shape and increase its perimeter. The bay shape also permitted the view of the interior from an angle when glare over the main face occluded the vision through.

The shop front window was tall enough to cover the entire height up to the beam-bottom or the bottom of a projected floor above. It provided ample daylight, necessary for many North European locations. However, in S. Europe and other countries the shop front glass was stopped at door height level, covered by the sloping awning or used for translucent shop sign board.

Exterior shop front display substantially depended on day light for illumination, whereas interior display units were nearly dependent on artificial illumination.

Over the years the shop-fronts have changed mainly for FOUR reasons:

1. The quality of glass and size, both have improved since Industrial Revolution. Major quality improvements have been for clarity of glass, such as free of colour tinge, specks, bubbles and undulations. The size of glass has increased several times accompanied by strength. Safety glasses such as toughened or laminated glass requires no other protective layer like a metal grill.

2. The store formats have changed from a single owner and specific set of commodities or services, to departmental stores, malls’ mega marts.

3. Neighbourhoods have changed from a street of a row of shops with residence on upper floors to shopping centres like clustered shops, shopping arcades, multi level shopping centres.

4. The illumination technology has changed. From spot lights, diffused lights, neon tubes, CFL, glow panels to fibre optics, LEDs and LCDs.

All these have affected the nature of display windows. Earlier the glass panes were set within a wood-frame and divided by heavy muntins, as glass available then was of small size and brittle or breakable. Heavy mid members obstructed the clear view. Very thin muntins or glazing bars of metal T sections provided uninterrupted look. As larger sizes of glass became available, single unit glass shop-fronts became common.

Small pieces of glass, each reflected light differently so created a very patchy look, but the large piece of glass as a single unit had only one angle of reflection. Large pieces of display glass were engraved or ground with borders and corner patterns to ‘soften the look’. Large glass front require framing only at the edges, which are often concealed in ceilings, side wall panelling and flooring.

To reduce the glare folding canvas awnings were stretched over and nearly covering above-the-head level section of the opening during sunny days or hours. Tinted glass and polyester film coated glass are used to reduce the solar gain and UV damage to the goods displayed. At places like a beauty parlours, barber shop, it is possible to use heavy metal sprayed glass or overlay films that have nearly one way vision.

Friday, July 11, 2014


Chintz as apparel fabric
Calicut (Kozhikode, a port town in Southern most state of Kerala in India), was famous for its cotton fabric called Ka-liyan after the traditional weavers who were also known as ‘Ka-liyans’. Calicut was a major spices exporting centre, since 11th (or even earlier), where European seafaring traders were regular visitors. European traders found Indian textile-fabric to be a valuable additional trade commodity and introduced the Calico product to their home countries. Later Chintz, a solid-coloured or printed variety of Calico was brought to Europe.

The word Chintz derives from its original singular version Chint or Chhint, roughly translated as spotted. The Portuguese, called them pintado meaning, not painted but spotted. Chintz. Acharya Hemachandra (Hemchandra Suri a Jain Monk, 1089–1172 Gujarat, India) has mentioned calico fabric prints as chhimpa, or chhapanti (chhap=printed pattern or image), with a lotus design. During the Indian Sultanate period 1200onwards (pre-Mughal Era), printed cotton textiles were produced in Surat, Ahmedabad and of Gujarat, Rajasthan, and Madhya Pradesh of India. Chintzes for European markets were quite different from the local Indian designs, had new patterns such as flowers and birds, and swags.

The overwhelming popularity of printed cottons or Chintz material dulled the traditional wool and silk sales markets in England and France, leading to ban on import of dyed or printed calicoes from India, China or Persia. This led to import of grey-clothes (unfinished -washed, dyed or printed textiles. The grey-clothes were reprocessed and printed in southern England with the popular patterns. 18th C saw a great market in many European countries for the incredible cotton fabric that was bright, colour-fast, and had exotic patterns. Chintz was initially used for wall and bed hangings. But soon enough it was liked by everyone in the society as apparel material due to its lightness, comfort and beautiful designs.
Fashionable London actor David Garrick and his wife had their chintz bed hangings confiscated by English customs.
Chintzes were fabrics glazed with starch and calendered with wax. These were in later periods were heavily ironed or burnished with a shell or beaten with wooden mallets to produce a shiny surface. The finish was however, very temporary, yet very widely used for its luxurious appeal in furnishings and formal apparels. Post Industrial revolution periods several chemical-based permanent glazing processes were developed. Unglazed fabric is known as Cretonne.

The term mordant derives from a French word mordre =to bite, as it was thought that a mordant helps the dye to bite onto the fabric, to hold fast during washing. A mordant is often a polyvalent metal ion. Mordants include tannic acid, alum, urine, chrome alum, sodium chloride, and certain salts of aluminium, chromium, copper, iron, iodine, potassium, sodium, and tin. The Mordant + Dyes combination (pre-mordant, meta-mordant or post-mordant) operates in one of these methods: 1. The substrate is treated with the mordant and then dyed, 2. The mordant is added in the dye bath itself, and 3. The dyed material is treated with a mordant.

Madame de Pompadour wearing Chintz dress in painting by Fran├žois-Hubert Drouais 

Sunday, July 6, 2014


From ancient times THREE different classes of materials have been handled by human beings.

1. Materials like Clay with important quality of plasticity that allowed the shaping at ambient temperature.
2. Materials like Wood and Stone were re-shaped by removal of the mass.
3. Metals were workable in both the manners, shaped by heating and beating (forging) and removal of the mass.
One may include Weaving as a different class of ‘material formation process’. Though, weaving is often categorised as a method of ‘material composition’ rather then a ‘forming-shaping’ process.
Needle Craft tools

Many Techniques of Materials handling in use today are essentially the same as those employed in ancient times. Several of the material handling techniques have originated from day to day living such as cooking, farming, home building, storage management and rituals.
Over the ages the techniques of materials handling have been refined in terms of the tools used, and rationalized in terms of procedures. Many processes are now highly mechanised saving time and energy, and some even are fully automatized, using programmed automats and robotics that allows faster, accurate and safer production.
Ancient stone tools

Some important techniques of associated with material handling are briefly discussed in following FOUR groups.
1          Techniques for material handling by reshaping the form such as plastic moulding, casting, extruding, pressing, shaping, embossing, reforming, deforming, removal of material, stretching, compressing and forging.

2          Techniques for material handling by application of foreign materials or material deposition such as alloying, embellishing, cladding, layering, fixing, etc.
3D Printing Material Deposition

3          Techniques of for materials handling by composition, such as assembling, entwining, joining, tying, bracing, weaving, embroidery, stitching, etc.
Industrial multi tasking Robots

4          Techniques of for materials handling by ‘composite’ forming through the Matrix and Filler concept, such as layering, particle composites, etc.
Composite forming- corrugated boards

Cutting is the oldest of all techniques of material finishing. First cutting tools were made of sharp edged flint stone chips. These helped in cutting meats for food and for cleaning the hides. Later cutting stone chips were tied to wood or bone handles for better tool holding and leverage greater force. Cutting Axes were reasonable for medium strength materials like wood, but, for harder materials like stones, cutting and beating actions were separated into hammer and chisel. Hammering was also used for grinding food, breaking and crushing nuts and compressing leather. Cutting was used for fast division of materials and quicker removal of parts of materials (skinning, shaving, debarking, chopping, mining). Cutting was the crude but primary technique of material processing.
Hammer - Material deformation

Carving is a controlled cutting technique requiring use of a chisel and only occasional pounding by a hammer. Carving is associated with fine but soft grain materials like ivory, horn, bones and wood. Carving is also done to pliable metals like copper, silver-based alloys, and also hard but fracture-able materials like stones.
Wood turning Lathe

Engraving like the carving is a material removal process, but more delicate and shallower. It was done with sharper and narrower points and with only hand pressure or very light pounding of the hammer. Engraving is today done by fine rotary tools similar to the dentist’s pneumatic drill. A computer controlled, diamond bit engraving is now also done to ultra thin materials. In Intaglio, or Gravure, printing, the image to be printed is etched or incised into the surface of the printing plate or cylinder. Gramophone records and Computer disks have engraved and embossed grooves. Engraving is now, carried out by laser process rather then sharp points.
Chasing is engraving, but in small length linear-strokes or in continuous linear patterns. The material is either depressed or displaced by a fine tool as dots. Historically wet ceramic pieces and plastered-surfaces (writing tablets- Cuneiform) were rendered by chasing. Braille writing on a thick paper sheet is a form of chasing. Engraving and chasing techniques are frequently used to provide a matt finish, onto normally very glossy stainless steel surfaces. Chasing techniques are also used for relieving as well as introducing stresses at the surface section, for facilitating greater moisture or heat transfer, and to improve the ductility of the material.
Embossing is a technique of form deformation or mass reshaping of a sheet like material. It introduces a texture through pounding, beating or by pressing of the surface. The pressure may be applied from one face or both faces of a sheet, locally as spots, or continuously under a plate or roller, creating repeat patterns or random designs. Pounding or beating compacts, the surface-sections of the material, and thereby increases its density and integrity. Embossing techniques are used to reduce the gloss by matting the surface. Embossing is done to increase the thickness bulk of very thin surface materials and make them apparently stiffer. Synthetic fabrics and fibres are emboss-deformed and permanently set (perma-set and texturizing) through heat or chemical treatments.
Repousse is a method of raising a design in relief from the reverse side. There are three essential types of tools used: -for tracing, -for bossing, -for chasing. Ornaments in relief are also produced by mechanical means. A thin, pliable sheet of metal is pressed into moulds, between set of dies, or over the stamps. Embossed utensils of copper and brass, statuettes of gods formed of thin silver and gold plates are very much part of every Indian house. Today Aluminium craft pieces are similarly embossed and black anodized.
The design is first drawn on the surface of the metal and the motifs outlined with a tracer, which transfers the essential parts of the drawing to the back of the plate. The plate is then embedded face down in an asphalt block and the portions to be raised are hammered down into the soft asphalt. Next the plate is removed and re embedded with the face on top. The hammering is continued, this time forcing the background of the design into the asphalt. By a series of hammering and re embedding, followed finally by chasing, the metal sheet attains the finished appearance.
Traditional Indian Brass and copper utensils have hammered finish on the outside. The same is often copied on aluminium utensils but reducing the strength due to ‘cold working’ of the metal. Leather and paper surfaces are rolled embossed to create textured patterns. Timber veneered surfaces are pressed for texture creation. Rendering of a wet plaster face by variety of pressing and chasing tools is very common. Chasing is very common with copper and brass pots (e.g. Peshwai Lotas and glasses).
Matting is mainly used for creating textured surfaces. Matting is a mechanical technique compared to etching where a chemically active substance is used. Mating and etching can also be done by chemical metal removal processes (such as by reversing the metal deposition by changing the cathode charge) in the final stage of plating. Parallel, crossed, irregular, concentric, circular and other geometric configurations are carved or embossed on the surface. In matting process very fine lines or dots are created. Matted areas contrast with other glossy areas.
Matting of Surface

Etching is usually done by an active or reactive chemical substance that will either erode away part of the surface or change its colour quality. Acid and alkali treatments also provide etched surfaces. Etching is also an artwork technique of Hydrofluoric acid over Glass surfaces.
Concrete surface levelling

Surface levelling is a major field of material handling. Surfaces are levelled by chipping away very thin sections off the surface. The material must have layered formation (e.g. Kotah -Ladi stones, bamboo, cane) or fracturable or brittle constitution (e.g. stones). Surfaces are ground and polished for a levelling. Surface levelling is done as plastering with materials like clay, lime, gypsum, etc. 
Shaving is done to remove material’s components such as outward hair or fibres, layers, etc. Leather surfaces are shaved to remove the surface hair and also for thinning. Leathers are also surface split to separate leather suitable for uppers and soles. The palm leaves are shaved to remove the stems and make them smoother for writing. Tree-barks are removed by axes and choppers to retard insect attack and increase moisture removal. Timbers are re-cut or planned with finer tools to achieve a smoother surface. Timbers are split very finely to create veneers. Wood planning is also a shaving technique. Carpets and rugs require close shearing by scissors to shave of protruding fibres.
Grinding removes material from the surface to roughen a normally glossy surface like glass, or polish a rough surface like stone. Grinding requires material of higher hardness than the surface material, and is done by rubbing down with a graded series of coarse to fine abrasives, such as Carborundum, sandstone, emery, pumice, sand, glass and diamond powders. Where a material constitution permits, very fine grinding may polish the surface. Grinding is a cutting operation in which each grit that comes in contact with the material cuts out a minute chip, or swarf. Grinding wheels usually consist of particles of a synthetic abrasive, such as silicon carbide or aluminium oxide, mixed with a vitrified or resinoid bonding material. Grinding can be coarse or fine, depending on the size of the grit used in the grinding wheel. Metal and glass can be ground to a mirror finish and an accuracy of 0.0000025 cm. 
Abrasives are used as grinding wheels, sandpapers, honing stones, polish, cutoff wheels, tumbling and vibratory mass-finishing media, sandblasting, pulp-stones, ball mills, and many other tools and products. Stone surfaces are chiselled to split the material into thinner sections, to remove the weathered crust and also to level out the surface. Grinding and polishing is done to: Hard materials such as building stones, marbles, granites, metals, glass; Precious and Semiprecious stones like gems, diamonds; Animal products like ivory, bones, horns, teeth, leather; Plant products like timbers, seeds; Ceramics like pottery products, bricks, cement concrete and other cement products.
Polishing, Honing, Lapping, Buffing: Polishing uses extremely fine abrasive substances, such as jewellers rouge, Tripoli, whiting, putty powder and emery dust to rub or burnish an extremely smooth and brilliant finish on the surface of a material. The polishing materials are coated on the surface of cloth, felt, leather, rubber pr polymer wheels or as belts. Metal surfaces are levelled and finished by honing and lapping. Honing removes less than 0.0125 millimetres of material from the surface to eliminate micro scratches and machine marks from ground machine parts. It is done with bonded abrasive sticks or stones that are mounted in a honing head. Lapping is a process in which a soft cloth (wool, linen and chamois-leather) impregnated with abrasive pastes (rubbing compounds), is rubbed against the surface of a workpiece.
Buffing is a term used for polishing of metals. Buffing is done with polishing compounds and brushes of various shapes, and abrading materials, like: (animal hair, synthetic fibres, plant fibres -coir), flex, wool and leather. Barber polishing the razor on a leather stripe is a buffing process that levels out small nicks on the blade. Utensils are buffed for a polished surface.
There are four types of precision grinding machines: Centre-type grinders used for tiny valve spools to steel mill roles. Centre-less grinders used for bowling balls, surgical sutures, and tapered roller bearings. Internal grinders are employed for inside diameters of gears, bearing races, and similar parts. Surface grinders are used for die tops, bench surfaces.
Lapping is used to produce a high-quality surface finish or to finish a workpiece within close size limits. Dimensional tolerances of 0.00005 millimetres can be achieved in the hand or machine lapping of precision parts such as gauges or gauge blocks.
Burnishing is controlled burning (or a heat treatment) at the surface section to remove part of the material and to change the colour or texture properties of the surface. Burnishing is both a process of surface finish and surface cleaning. Most of the organic materials can be surface-treated directly with fire or indirectly with high heat to achieve a burnished or ironed effect. Textiles, paper, leather, leaves, wood, etc. are some materials that can be burnished. High temperature burnishing removes the surface fibres and hair, and chars or burns (sinter) the top part of the surface, creating a burnt colour + texture effect. Textiles are Ironed, i.e. decreased or perma-set, i.e. creased with pressurized heat treatment. Synthetics or composite textiles are selectively or locally burnished to fuse the fibres or filaments, create textured effects and also alter the transparency, opacity, etc. Wood surfaces on burnishing, creates a dehydrated or an old shrivelled or shrunk surface, similar to an old wood.
Metal surfaces also burnished not only to harden or anneal the top surface but to burn the oily residues, dehydrate, and descale the surface. Burnished metal surfaces often attain peculiar colour and pattern effects.


  Post 171 -by Gautam Shah .  SUNDAY Feature on ART of Architecture John Terrick Williams (1860-1936) was a British painter, who was a me...