PERSONAL AND BUILDING SAFETY –a List + Links to Blogs

Post 658 -by Gautam Shah

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Detectable_Warnings

ANTI-LIGATURE –Issues for Design -8 https://interiordesignassist.wordpress.com/2016/06/28/anti-ligature-issues-for-design-8/

ANTI-LIGATURE https://interiordesignassist.wordpress.com/2014/04/04/anti-ligature/

SAFETY ASPECTS of DESIGN https://interiordesignassist.wordpress.com/2016/04/15/safety-aspects-of-design/

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SECURITY in BUILDINGS https://interiordesignassist.wordpress.com/2015/01/05/security-in-buildings/

DOOR SECURITY https://interiordesignassist.wordpress.com/2014/07/13/door-security/

SPACE PLANNING and NON VISUAL CUES https://interiordesignassist.wordpress.com/2015/04/17/space-planning-and-non-visual-cues/

MANAGING the RISKS https://interiordesignassist.wordpress.com/2014/11/03/managing-the-risks/ 

Risk on Brinks

DE-WINDOWING http://talking-interior-design.blogspot.in/2016/11/de-windowing.html

FENCES https://interiordesignassist.wordpress.com/2014/08/28/fences/

GUARD RAILS https://interiordesignassist.wordpress.com/2015/04/08/guardrails/

COMPONENTS of RAILINGS https://interiordesignassist.wordpress.com/2015/05/04/components-of-railings/

RAILINGS AND PARAPETS https://interiordesignassist.wordpress.com/2015/01/12/railings-and-parapets/

GRILLS https://interiordesignassist.wordpress.com/2014/09/30/grills/

TYPES of BARRIERS https://interiordesignassist.wordpress.com/2016/01/07/types-of-barriers/

MANAGING the RISKS https://interiordesignassist.wordpress.com/2014/11/03/managing-the-risks/

ECONOMICS of RISKS https://interiordesignassist.wordpress.com/2014/11/10/economics-of-risks/

Door of a traditional Indian House

Sheth ni Pol Ahmedabad --a gated community

City Gate Prem Darwaja Ahmedabad

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WORK PROCESSES -simplified overview

Post 657 -by Gautam Shah

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Workshops till middle age were craftspeople oriented. Mechanical power drives allowed heavy duty jobs and precision or micro work. Mechanical devices like gears, leather belt transmission and need for greater productivity by exclusive task assignment provided standardized products on a massive scale. Some degree of linear production planning was occurring. The power shaft forced organization of workshops on linearity. The line production methods promoted productivity through time management and sequencing of task procedures. In many instances tasks began to be assimilated and handled simultaneously in a single time slot.

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power shaft pulley beltsDuring the early part of the 20th C. machines became adjuncts to assembly-line production systems and multi tasking. For this machine became a device to handle a variety of tools, often simultaneously. The machines were operating at a faster speed requiring equally fast control system.

595px-Machine_shop_in_the_Government_Printing_OfficeMechanical power transmission systems were concurrent systems for the entire workshop, but the impediment was removed with the electric power. Electrical power offered local control through an electric motor (horse power) rating, speed variation through voltage control, and operational control like start-stop, etc. Independent electric powered machines with faster and multi tasking capabilities, however, were now difficult for human supervision. Control devices were actuators, for process regulation.

workers with shaft power transmission

Control devices or systems are of two types: A Feed-forward system has inputs or predicts unusual happening, but would not oversee or govern the actualization of the action. A Feedback system improvises strategy for future actions in many instances oversees actions being taken.

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Feed-forward systems: Jacquard weaving loom uses a feed-forward control as a programmed punched card to weave a pattern, but cannot stop the loom if there is a short feed of thread. Similarly a cutting machine cuts a large sized shape by moving the cutter tracing a small scale pattern through the arm of a pantograph.

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Feedback systems: A wind mill keeps facing the wind with the help of a tail wane. A pressure cooker seals itself with heightened internal pressure of steam. Pressure valves are weight calibrated opening themselves at certain pressure levels only.

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Control devices and systems have led to automation of processes. Automation began in the late 1940s with the development of the mechanical devices for moving and positioning objects on a production line, though observation and manual intervention were necessary. During 1960s digital computers began to offer control systems in three different manners: For supervisory or optimizing control, Direct digital control, and Hierarchy control. In the first instance, for the supervisory control a computer sets parametric levels for optimizing the operations. In the second instance, for the direct-digital control, several devices feed data to a single processor, which then decides a strategy of operation. The advantage here is very fast and objective evaluation of the data. The third system the hierarchy control applies to all the plant-control situations concurrently, often with the actuation of the control mechanisms.

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BLOGS LINKS about PERCEPTION

Post 652 -by Gautam Shah

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These are my select few 91+ blogs (out of nearly 850 placed on my 3 blog sites) written over last 2 years, now compiled under a common theme ‘Space Perception’ with following sub sections.

  1. SPACE PERCEPTION
  2. ILLUMINATION
  3. MOVEMENT, BALANCE
  4. OPENINGS SYSTEMS
  5. GLASS
  6. GRILLS, TRELLIS, CURTAINS
  7. SOUND and NON VISUAL
  8. OBJECTS, SURFACES, COLOURS, PATTERNS
  9. REALITY, MAKE-BELIEVE

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1 SPACE PERCEPTION

1.1 PROCESS of PERCEPTION

1.2 PROCESS of PERCEPTION part-I

1.3 SPACE PERCEPTION -through seeing, hearing and touching

1.4 SPACE PERCEPTION – Issues for Design -4

1.5 SPACE PERCEPTION

1.6 SPATIAL DEFINITIONS

1.7 SENSING OBJECTS BEYOND THEIR SIZE MEASURES

1.8 SPATIAL DEFINITIONS

1.9 SPATIAL DISTANCING and BEHAVIOUR

1.10 DISTANCING in SPACE

1.11 SPACES SIZES and SHAPES

1.12 SMALL SPACES and LARGE SPACES

1.13 REACH in SPACE

Scaffold Building Manhattan New York City Taxi

2 ILLUMINATION

2.1 CONTRAST EFFECT – PERCEPTION

2.2 PERCEPTION of SPATIAL FIELDS -ILLUMINATION

2.3 DAYLIGHTING

2.4 DAY-LIGHTING – in Interior Spaces

2.5 DESIGN CONSIDERATIONS for DAYLIGHTING

2.6 SPACE PERCEPTION and ILLUMINATION

2.7 DAYTIME INTERIOR ILLUMINATION -REALITY and PERCEPTION

2.8 INTERIOR ILLUMINATION through DOORS

2.9 WINDOW LOCATION and NATURAL LIGHTING

2.10 LE CORBUSIER and ILLUMINATION

2.11 COMPARING WINDOWS of FLW, LC and Mies

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3 MOVEMENT, BALANCE

3.1 MOVEMENT and BALANCE – Issues for Design -5

3.2 PERCEPTION of BALANCE and MOVEMENT

3.3 BALANCE in DESIGN – Part 1

3.4 BALANCE in DESIGN – Part 2

3.5 VISUAL PERCEPTION of MOVEMENTS

3.6 PERCEPTION through SCALES and CONVERSIONS -Issues or Design -3

Landscape

4 OPENINGS SYSTEMS

4.1 LEVELS of OPENINGS

4.2 DESIGNING OPENINGS

4.3 CLASSICAL WINDOW FORMS

4.4 ARCHITECTURAL WINDOWS and VISION in-out

4.5 ARCHITECTURAL WINDOWS and the MEANING

4.6 ARCHITECTURAL WINDOWS and MECHANICS of VISION

4.7 MEANING of a WINDOW SILL

4.8 THIRD DIMENSION of OPENINGS

4.9 LANTERNS in ARCHITECTURE

4.10 CLERESTORY OPENINGS

4.11 SKY LIGHTS

4.12 ROOF LIGHTS

4.13 SHOP WINDOWS

4.14 SHOP WINDOWS – SHOP FRONTS – DISPLAY WINDOWS

4.15 FRAMING of OPENINGS

4.16 MASKING of OPENINGS Part -III -Framing

4.17 MASKING of OPENINGS Part -II

4.18 MASKING of OPENINGS Part -I

Eating_Alone

5 GLASS

5.1 GLASS in ARCHITECTURE -1

5.2 GLASS and PERCEPTION

5.3 GLASS in WINDOWS – Part • I

5.4 GLASS in WINDOWS – Part • II

5.5 COLOURED GLASS

Fixing Metallic Transparency Glass Front Metal

6 GRILLS, TRELLIS, CURTAINS

6.1 CONTEXT -Issues for Design -12

6.2 ROOFS 3 -Skyline and Silhouette

6.3 HOLISM and DESIGN

6.4 TRELLIS

6.5 GRILLS

6.6 CURTAINS

6.7 TRANSLUCENCY for CURTAINS

6.8 SHEER FABRICS and CURTAINS

6.9 SHEER FABRICS and CURTAINS-

6.10 NON SILK SHEER FABRICS and CURTAINS

6.11 WEIGHT and TRANSLUCENCY of fabrics for curtains

6.12 SHEER FABRICS

Religious Kneeling Worship Pray Prayer Church

 

7 SOUND and NON VISUAL

7.1 SOUND

7.2 SOUND, SPACE and PERCEPTION

7.3 PERCEPTION of SOUND and SPACES

7.4 SPACE and SOUND REVERBERATION

7.5 SOUND and NOISE MANAGEMENT

7.6 HEARING and interior spaces

7.7 ACOUSTICS in SMALL SPACES

7.8 SOUND and SMALL SPACES

7.9 SPACE PLANNING and NON VISUAL CUES

7.10 NON VISUAL LANGUAGE -Issues for Design -6

7.11 LANGUAGE EXPRESSION and SOUND PERCEPTION

wuzhen-1643267_6408 OBJECTS, SURFACES, COLOURS, PATTERNS

8.1 OBJECTS in SPATIAL FIELDS -Issues for Design -14

8.2 COLOURS -Perception and Expression

8.3 COLOURS and BUILDINGS

8.4 FLOORINGS

8.5 FLOORING COLOUR

8.6 FLOORINGS IN INTERIOR SPACES

8.7 PERCEPTION of SURFACE FINISHES

8.8 GLOSS

8.9 TEXTURES and MATERIALS

8.10 JOINTS in SURFACE FINISHES

8.11 MOSAICS

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9 REALITY, MAKE-BELIEVE

9.1 SOLIDS and VOIDS -issues for Design -13

9.2 AUGMENTED REALITY

9.3 SPACES and REALITY

9.4 MAKE-BELIEVE in INTERIOR 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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PASSIVE VENTILATION in Buildings

Post 648 -Gautam Shah

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Passive ventilation sustains good quality of air in interior spaces. It works on circulation or movement of air without the use of power utilities. It relies on principals of source management and dilution, rather than any filtration. Passive ventilation is substantially based on the quality of built-form and to a smaller extent on immediate surroundings. It is a very important method of adjusting heat and moisture in Hot-arid and Hot-humid climates. The quality of air is determined by temperature, moisture content, presence and proportion of ‘other’ gases and airborne particulate matter. The quality of air has important bearing on our body. A body may endure or adopt to certain abnormal conditions for a period of time but there may occur side effects. The side effects may be realized in a different form and at a different time.

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Passive ventilation relies, as much on external or macro conditions, as the interior spatial lay. It is based on three factors:

  1. Air movements due to the differing pressures and temperatures and the buoyancy forces that result across a building and its surroundings,
  2. Location of tasks and activities that support or hinder such patterns of air movements, circumstantial and designed apertures in the building shell.
  3. Factors that define the ventilation in a building are, space-profile (section), base levels of inward-outward nodes of ventilation, nature of surroundings and neighbourhood, sill level, depth and its profile-shape, task-intensive operative plane and its volume, and constraints enforced by elements such as size and shape of external overhangs.

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Passive ventilation occurs with Two major operants.

Differential air pressures are formed by wind movements in the immediacy of the building, the pattern and size of the buildings scheme and individual components of the building. Air movement also occur as a buoyancy effect caused by the temperatures of surfaces and surroundings near the wind-ward and wind-off sides. Air pressure difference occurs, across buildings’ interiors and exteriors, across the openings and temperature of surfaces and surroundings, near the windward and wind-off sides. Entry and exit point for air, though continually shift around due to the changes in pressures.

Desert City Oasis Town Ait Ben Haddou Oasis

Temperature differential depends on the direction and inclination of sun, climate, seasons of the year, local massing of the shadows, surface materials, vegetation, water bodies, and presence of heat evolving entities. Dark surfaces and thin body objects warm up very fast and begin to radiate the heat, creating local heat related buoyancy in air.

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Ventilation requirements vary depending on whether one wants to gain or lose heat, add or subtract moisture, dilute or remove ‘other’ gases and airborne particulate matter contaminants. Ventilation needs change depending on, distance of space occupation from the inlet-outlet for air, functional use of space, types of tasks, work-schedules, crowding in the space and presence of heat evolving means (hearths, machines, etc.). One important aspect is the feeling of air movement near-over the body. It depends on several factors such as air velocity, fluctuations in air velocity, temperature of air, and personal factors like overall thermal sensation and activity level. Even for the same person, sensitivity to air movement may change from day to day.

635px-Wall_Decoration_at_Kesava_Temple_in_Somanathapura_retouchedDraughts (Draft) are very low velocity air movements. These are not always perceptible, as they do not cause any sensation of pain or pressure on skin. Draughts are more felt due to air pressure thresholds near cracks and such leakage points in small and enclosed spaces. Draughts, however, help in convective heat exchange, evaporation and dilution of pollutants in air. Draughts cause localized cooling or heating of sensitive organs of our body.

Breeze or low to medium velocity air movements generally affect only local areas. Breeze does not let airborne particulate matter to settle down. Skin sensation can be avoided by appropriate screening and deflection of the breeze. Since breeze causes effective pressure on skin, with very immediate and very perceptible change sensation.

Winds are high air velocity movements of air affecting larger regions. Winds raise particulate matter in the air, cause rapid change in level of humidity and often cause discomfort due to high pressure sensation on the skin.

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In hot and cold both types of climates people often close all the openings to reduce the air movements and thereby control the convective heat gain or loss. Turbulent air velocity is less comfortable than a Laminar air velocity. Turbulent air movement achieves a better mix of air whereas laminar helps in greater displacement of air mass. This is the reason why in hot arid climates small size openings are used to create turbulence or a viscous flow, and in hot humid climates the body level openings of horizontal nature create a laminar flow to displace the humidity.

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Passive ventilation occurs through macro and micro openings. Macro or formal openings (doors, windows, gaps etc.) are designed with a characteristic size, shape, passage section, adjunct elements on internal and external faces, and occur close to the location of need (for ventilation). Micro openings are circumstantial, and are much smaller in size like cracks, crevices, gaps or apertures. Micro openings offer a passive and consistent ways of managing comfort in enclosed and semi-open spaces. These manifest as intentional gaps, unplanned crevices and cracks of structural stresses. Both, macro and micro openings can be broadly be classified by their locations.

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  • Roof level openings are such as in the thatched and country tile roofs, loosely laid roof slates, stone sheets, or intentionally placed micro passive vents such as lattices, chutes, hoppers, etc.
  • Upper section openings in walls are such as the unpacked ends of corrugated sheets or roofing tiles, ends of purlins and truss and eyelets or oculi like holes and lites in gables.
  • Other openings manifest as doors, windows, cut-outs, chowks, in joinery, leaky fitments, ajar shutters, door bottom space, peep-holes, latticed constructions such as of woven mats or fabrics, louvered openings, crack or fissures in building elements, expansion joints, unsealed joints, etc.

Movement of air through openings encourages evaporation and increases cooling in the interior space. In dry arid climates dwellers locate their activities in the strongly directional air movement formed by small and deep-set openings. Deep-set openings also increase absorption of heat in the mass of the structure. Simple passive cooling devices such as water wetted grass mats or fountains help cooling. Outside air has lesser moisture (except during raining conditions) then indoor air, so any level of ventilation, dilutes the interior humidity level and adds to the comfort.

620px-AlfedPalmersmokestacksAir borne particulates arrive from outside sources like heavy vehicular traffic, polluting industry (mines, thermal power plants, mineral grinding plants, in the vicinity, or sand storms, and internal sources like cooking or craft fuels, and processing materials (grinding, spinning-weaving). Outside particulate can be controlled by changing the ventilation gaps to different location or elevation. Filtration screens occupy more then 60% of opening area, and much lesser due to frequent choking. Dynamic screening like water bodies or sprays can be useful, but costly and perhaps beyond the concept of a passive device. Non turbulent wind flow helps in keeping the particulate matter to lower sections.

Moisture control in interior space occurs by dilution, greater air movement and siting management of moisture generating amenities. Isolation of cooking, washing, bathing areas in dwelling is a common practice in hot-humid climates.

Quality of indoor air mainly depends on the external circumstances. The ‘feel-good aspect’ in a tropical climate (hot-arid or hot-humid) zone is not only regulated by the obvious temperature, rates of movement (pressure) and the moisture content, but also by the level of fouling of air. Some experts have claimed that air quality of a room is chiefly determined by its CO2 concentration. In tropical buildings concentration of CO2 and other gases is not a critical factor, as numerous openings and micro gaps remain substantially open. Location of cooking area is a segregated entity or an outdoor activity, and like cold climates no interior fire places.

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SURFACE MODIFICATIONS

Post 647 -by Gautam Shah

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Natural and Industrially-produced materials require some form of surface modifications or treatments, before being put to functional use, or for readying them for the next process. Surface modification at a basic stage, consist of cleaning and mechanical scrubbing. The surface modifications are for creating use-worthiness by levelling, texturizing, or for application of additional materials for shielding. The surface modification starts with visual observation and touch-feel experience that no foreign materials have remained on the surface, and all loose (removable) materials are removed. These simple processes ensure integrity of the surface.

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The next level of surface modifications are applications like coating, physical-chemical treatments, cladding, mounting, plating, joining, welding, levelling, cleaning, washing, ph balancing, static removal, etc. Surface modifications are intently surface preparation processes and may impart radically different surface qualities such as textures, ionization, etc.

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At another level Surfaces Modifications are not attempted, but such situations are negotiated with technologies. These include defining means to override the hindrances of texture, handling issues, electrical and other properties. These technologies also include forming shields around the users, tools and other equipments rather then over objects. The shields are physical layers and non-physical arrangements like restricting the exposure through time-space management.

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In early ages, the surface modification and applications were an integrated process for exploiting the surface of any object. Primitive arts and crafts had a comprehensive treatment that consisted of 1: Modification of the surface, 2: Application of surface forming materials, and 3: Rendering new textures and tonal variations or shades. At a later stage an additional treatments for protection of the new surface were devised.

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Surface modifications are physical, chemical and mechanical processes.

The Physical processes are mainly used to remove unwanted particles or materials (such as rust, nodules, residual deposits, dust or grease, lubricants, cutting-oils, etc.) adhering to the surface. Rubbing, air-dusting, vacuum cleaning, wiping, water-bathing, etc. remove such adhered materials. The particles have remained on the surface due to the holding by surface texture, bonding or ion attraction, and horizontal storage. Washing with soap or a surface active agent (surfactant) can weaken the ion attraction break the weak molecular bond generate by-products that can be removed easily.

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The Chemical processes include acid-alkali treatments and solvent washing. The processes roughen, etch or smoothen the surface. In many instances the resultant by-product is beneficial or neutral, and so allowed to remain on the surface. In other instances a secondary treatment is required just to remove the by-products of the first treatment. Sometimes Surface preparation agents themselves are the primary surface finishes. Such agents cover the surface area as an intermediary film. Such films help in bonding of the final surface finish. Chemical processes also include burnishing, flame-treatments, surface annealing and hardening, cathodic modification, sputtering and material’s depositions.640px-A_brass_utensil

The Mechanical Processes affect the surface superficially. Cleaning of the surface by removal processes include abrading, grinding, rubbing, blasting, planning, chipping, etc. Other mechanical processes alter the surface with newer textures by engraving, patterning, planning, surface deformation, etc.

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Surface modifications processes have been used for body painting, pottery, home building, agriculture, mural or wall artwork, adornments, jewellery, ornamentation, household utilities, tools, musical instruments, etc. Surface modifications were explored pattern making, texture creation, personalization, cultural expression, totem, abstract or symbolic representation etc.

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Surface levelling is achieved by scrubbing or rubbing off the impurities, removing select protruding sections, or by skinning the entire surface area. In later cases there are chances of removing a seasoned or matured face and exposing a fresh one. Partial scrapping of the surface creates qualitatively unequal zones. This is the reason why over the ages levelling ‘plasters’ have been preferred. The ‘plasters’ can be thin coating, or an application of thicker mass. These were often rendered with patterns and textures or ‘loaded’ with minerals and colourants. Wet surfaces were, either, engraved or embossed with patterns to encourage the penetration of colours, to produce a bas or relief effect, or provide a highlighting boundary to the drawn object. Colours were blown as dry powders or applied as pastes and dabbed (pressed) into the wet plaster.

Gesso, a mixture of plaster of Paris (or gypsum) with size, is the traditional ground. The first layer is of gesso -grosso, a mixture of coarse, un-slaked plaster and size. This provides a rough, absorbent surface for ten or more thin coats of gesso sotile, a smooth mixture of size and fine plaster previously slaked in water to retard drying. This labourious preparation, however, results in an opaque, brilliant white, light-reflecting surface, similar in texture to hard, flat icing sugar.

Other related Blogs

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PAPER as a SHEET MATERIAL

Post 646 –by Gautam Shah

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Paper is a sheet form of material, and substantially used in sheet-form. Paper’s chief raw material is cellulosic pulp. It is also used in ‘non-planer’ forms, such as moulded products (egg crates), packing cases (glass), mould dummies, and as Papier-mâché.

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Paper pulp egg Cartons Wikipedia Image by Edward Betts

Paper as a sheet material is available with many different properties. It can be rough, smooth, grease-proof, water absorbent, water repellent or resistant, soft as cotton, stiff as board, heat resistant, fireproof, combustible, chemically resistant opaque, translucent, transparent, coloured, glossy, dull, strong, weak, tear-able, non-tear-able, light heavy, pulp-able cellular, waxed, sanded, embossed hinged corrugated, easily folded and pierced, coarse, fine or flocked.

Paper is mainly used for writing, printing, drawing, painting signs and images. Paper has many functional uses like wrapping, filtering, absorbing, insulating, protecting (Thai umbrellas), cleaning, mopping, polishing, buffing, toys and product forming, mould making, engraving, etching, embossing, medicare dressing, garment making, and for glazing (Shoji for windows and Fusuma for room dividers). Other uses include mask making, light canoe or boat making for races, single-use construction forms, casting die dummies, kites, lanterns carnival floats, tubes, textile bobbins and cones.

Pen_box,_signed_by_Mohammad-e_Ebrahim,_Iran,_1694_AG D,_papier_mache,_oil_paint_-_Aga_Khan_Museum_-_Toronto,_Canada_-_DSC07051

Pen box of Papier Mache with Oil coating Iran 1694 (Now in AK Museum Canada)

Paper pulp is used in various sheet form composites. Fiber boards are products engineered at a pulp stage. Various products differ in terms of nature and level of ‘pulping’, pressing technologies (pressure, temperature, curing used), wet or dry process of manufacturing, additives (both filler and bonding) and surface treatments. The products include high-medium-low density boards (typically MDF), hardboard, ‘Masonite’ boards, pulp boards with gypsum, cement and other minerals, natural and synthetic fibre additives. These sheet materials are surface treated, coated, tempered, laminated, co-formed or co-extruded.

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Parchment Paper > Pixabay image by Geralt

Inferior plant materials and timber wastes are partly pulped to form a homogeneous mass. Such partly pulped mass, however lack the mutual particle bonding. Boards (and often pre-shaped forms) are created by steam-pressing and with aid of 5% bonding materials (typically Urea or Phenol formaldehyde). Portland cement, Gypsum and polymer emulsion adhesives are also used for forming building boards. Paper pulp boards of extreme light mass are coated with Gypsum, polymers and foam to form acoustic ceiling panels. Layered paper composites with phenolic compounds are used as circuit boards and electric insulation panels.

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Paper making in Hahnemuhle > Wikipedia image by Hahnemuhle PR 

 

Structure of paper as sheet material differs from other sheet materials:

  1. Papers unlike plastic films and metal films are fibrous.
  2. Paper is composed of single short fibres, arranged largely at random instead of a regular array as is the case with woven fabrics.
  3. Unlike cloth, felt or leather it is laminar, that is each fibre is disposed mainly in the plane of the sheet.

Paper, however, resembles other sheet materials in that its structure is anisotropic in its plane and most of the fibres are oriented along the grain or the machine direction.

Paper is mostly made from cellulosic fibres derived from plant sources. The fibres depending on their origin have different types of cell structures, and so provide unique character to the paper. Cellulosic fibres are hygroscopic and swell considerably when wetted, but retain strength and durability. Most plant materials also contain non-fibrous elements or cells. These are less desirable for the paper making, but are useful as a filler material. Until about 19 C. paper was produced by hand processes, and as a result had very distinctive local style, texture and properties. Through the 18th C the paper making process remained essentially unchanged. The linen and cotton rags were the basic raw materials, but increasing demand for paper was posing shortage of pulp raw materials.

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Packaging forms with Papier Mache > Wikipedia images by Berklas

Paper is manufactured from material resources that can be regenerated, and the product is a recyclable material. Major sources of cellulosic fibres for paper manufacturing are wood and cotton. Cotton fibres are used in the form of lints (seed hair left behind after ginning), staples, waste yarn and threads and rags. Lints require no processing, staples need length shortening, but yarns, threads and rags need undoing of all mechanical processes such as spinning and weaving. Cotton fibres offer strength, durability, permanence, fine formation, colour, texture, and feel.

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Modular ceiling Panels of Paper Pulp > Wikipedia image by Adamantios

Wood pulp has been the chief material for paper making, but where forest resources were scant, many alternative sources have been explored. These sources include: Cereal straws, plant stems, linen, jute, hemp, bamboo, cane (rattan), paddy (rice) straws, banana leaf, sugar cane waste bagasse and grasses like esparto. Paper made from such alternative pulps, and without an admixture of other fibre tend to be dense and stiff, with low tear resistance and low opacity. Often such fibres are desired as additives for producing paper for abrasives (sand-paper), cover stock and heavy-duty industrial papers. Such fibres are also used for strength in duplicating and manifold papers. Flax is grown expressly for high-grade cigarette paper.

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Synthetics: Paper like sheets > (https://pixabay.com/en/paper-colorful-color-school-paint-182220/) Image by AlexanderStein

Synthetic or man-made fibres provide certain advantage when compared to plant based materials for paper pulp. Natural cellulose fibres vary considerably in size and shape, whereas synthetic fibres can be made uniform and of selected length and diameter. Long fibres, for example, are necessary in producing strong, durable papers. There are limitations, however, to the length of synthetic fibres that may be formed from suspension in water because of their tendency to tangle and to rope together. Even so, papers have been made experimentally with fibres several times longer than those typical of wood pulp, and these papers have improved strength and softness properties. Natural cellulose fibres have limited resistance to chemical attack and exposure to heat. For such purposes synthetic fibre papers can be made resistant to strong acids, for example in chemical filtration. Paper can even be made from glass fibre, and such paper have great resistance to both the heat and chemicals.

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Golf ball rest pins of dissoluble wood Pulp (http://maxpixel.freegreatpicture.com/Golfing-Tee-Golf-Golfer-880532)

Rags (mainly of cotton) are used extensively where permanence is of prime importance such as for bank notes, legal documents and security certificates. Technical papers include tracing papers, vellums, and reproduction papers, high-grade bond letterheads, cigarettes, carbon, and Bible papers. Khadi (Indian hand made) paper is an example of high rag content paper.

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Rags sorting for paper making > Image by Lewis Hine (1874-1940)

Wastepaper is a major source for cellulose. By recycling the wastepaper the dependency for virgin fibre is reduced and the problem of solid waste disposal is minimized. However the difficulties like, gathering wastepaper from scattered sources, sorting mixed papers, and recovering the fibre from many types of coated and treated papers, make it a very complex problem. Waste Paper treatments for asphalt, synthetic adhesives, metal foils, plastic and cellulose-derivative films and coatings, printing inks, etc. pose acute problems in reuse of paper wastes. Wastepaper is of four main categories: High-grade, old corrugated boxes, printed news papers, and mixed paper. High-grades and corrugated stocks originate mainly in mercantile and industrial establishments. White paper wastes accumulate in paper conversion units and printing plants. Magazine stock comes from newsstand returns, but some comes from homes. Mixed papers come from collectors. Grey Board, cardboard or Packing carton papers are produced from recycled paper wastes. These are as single or multiply boards.

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Laminated-multi-layered paper products > Wikipedia image by Veganbaking.net from USA

In recent years Papers have been coated, layered or co-extruded with many other forms of sheets, films and membranes. These include, metal foils, polymer films, metalized polymer films, films formed through liquid coatings, in-situ foam forming.

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