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 4 blog sites) written over last 4 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 Metal6 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-2

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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WATER COLOURS

Interior Design Assist

640px-set_of_watercolor_paints_-_ariel_waldman Water colours > Wikipedia image by Ariel Waldman from Munice

The distinguishing characteristic of water-colour painting is its translucency. The surface of the paper is visible through the thin water-colour pigments. It creates a veil-like effect that is very distinctive from the heavy and opaque painting in oil. Water Colour paintings have been created on papyrus, bark papers, plastics, vellum or leather, fabric, wood, and canvas.

brushtypes Water colour brushes Wikipedia image by Vinegarten en wiki

Water-colour paints are produced by mixing dry powdered pigments with gum arabic (a natural gum of acacia trees). Solid water-colour cakes can be dissolved in water and applied to paper with a brush. Although water-colour is a relatively modern type of paint, but various water-based paints systems have been used throughout the recorded history. Water colours are usually transparent and seem of pure hue because the pigments are applied in a relatively…

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COLOUR MODELS (RYB)

Post 530  by Gautam Shah

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RYB MODEL Subtractive colors

The search for ‘truest’ or ‘purest’ colour has been a story of revelations. Some of the purest forms of colours have been available in nature, as flowers, body colours or spots over insects and birds. These were sought in applicable forms such as pigments and juices or dyes. It was realized from very primitive times that both the forms have distinctive applications. Pigments are good for wall-arts and juices or dyes are good for body colouring, fibres and leathers. Beyond this it was also known that pigments were comparatively opaque in comparison to nearly transparent juices or dyes. Primitive age craftspeople had typical understanding that very ‘pure colours shades’ were less lasting than slightly compromised shades. This realization was due to the fact that oxide and natural pigments were longer lasting or non-fading. A ‘richer’ shade of colour was sought by methods of purification or concentration through separation, grinding, washing, floatation, sieving, calcination or sintering.

Centre Le Corbusier, Zurich Wikipedia image by Author Absinthe.

Since prehistoric period it was also clearly known that richness of the colour lies in the contrast it creates with the nearby colour. Such an understanding of colour value is known only to the actual user of the colour and not to lay persons who can philosophize the effect. Realizations are not necessarily visual percepts. Through such attempts of definition first theories of colours began to emerge. Greek philosopher Aristotle related colours (as maintained in De colouribus) to the four elements: air, water, earth and fire. But then he was not a visual art practitioner.

Aristotelian world of Colours Land Sky Water Wikipedia image by Author Ikhlas Qassmi 13336

“For air and water are naturally white in themselves, while fire and the sun are golden. The earth is also naturally white, but seems coloured because it is dyed. This becomes clear when we consider ashes; for they become white when the moisture which caused their dyeing is burned out of them; but not completely so, for they are also dyed by smoke, which is black. In the same way sand becomes golden, because the fiery red and black tints the water. The colour black belongs to the elements of things while they are undergoing a transformation of their nature”. -Aristotle’s realizations of colours.

Since Aristotle’s time such ‘subjective realizations’ have found little favour with the art painters. Their triad of colours was of Red-Yellow-Blue of pure colours or un-creatable shades. But for many years, black and white remained baffling ‘colours’. One could mix few colours to match a ‘near-black’, but the same was not possible for white or ‘near-white’. The ‘disappearance of colours’ on a flying wheel and perception a white was not yet logically connected to this perplexity. It had to wait for Newton to explain it. Many painters before 1600s have written about creating and using colours, their ability to consistently reformat the same colour and also their inability to reformat the same shade in spite of all care and documented formulations. Describing a colour was even harder than creating it. The writings fail on how to state a colour shade. Colours have had only metaphoric interpretations.

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ColorTriad

Colour chart by Franciscus Aguilonius (1567-1617)

The Red-Yellow-Blue colour triad was the painters’ logic of defining the colours as per the visual experience. Franciscus Aguilonius (1567-1617) a physicist disputed Aristotle’s theory or rather the philosophy of colours. He devised a better method of identifying and arranging the colours. Colour arrangement was of placing 5 colours White – Yellow – Red – Blue – Black, at the bottom, and mixes of these forming the riser. He included the Red, Yellow and Blue which became the forerunner of other systems that function in a similar way. This was a chart, and not a colour wheel.

Wikipedia image > Goethe’s symmetric colour wheel with associated symbolic qualities (1809)

 

Runge_Farbenkugel

From Wikipedia

Aron Sigfrid Forsius (1611), a Finnish born astrologer, priest and neo-Platonist, and contemporary of Franciscus Aguilonius, derived a drawn colour arrangement with five main colours: Red, Yellow, Green, Blue and Grey, all placed for their affinity to Black or White. This, however, was going to change some 60 years later. In 1672, Newton showed the optical quality of colours, as a spectrum of seven colours. This was very different from earlier attempts of visual gradations of colours. This interpretation was challenged, by Goethe in the ‘Theory of Colours’ (1810). For him it was important to understand the human reaction to colour, compared with Newton’s science supported explanation. But at that time there were few takers for it. Newton first divided the spectrum in five main colours red, yellow, green, blue and violet but later included orange and indigo, to analogize with the seven notes in a musical scale, and perhaps the solar system, and days of the week.

A linear representation of the visible light spectrum wikipedia image by Author Gringer

Richard Waller in Stockholm published a list of 119 colours arranged from ‘dark to light shades’ in seven columns each topping with a basic colour. Jacob Christian Schäffer a German a natural historian and inventor wanted some standard format (Table of physiological colours, mixed and Simple, in 1686) that would permit unambiguous descriptions of the colours of natural bodies. This was the beginning of naming, identifying and graphically specifying the colours.

probably Claude Boutet’s 7-color and 12-color color circles Wikipedia image

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BLACK Part – II

Post 517  by Gautam Shah

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Black soot covered walls Almeida Júnior – Country Kitchen – oil on canvas 1895

Black is one of the prime colours, used by humans. Red, though is very vivid and fascinating colour in the history. Red and Black have ethereal connection, and both seem almost indistinguishable in monotone perception. This was one of the reasons that in the black-white cinema era, heroines avoided red dresses and lipsticks. The infamous Psycho shower scene of blood, was shot with not red liquid but most palatable chocolate syrup. The BW movie Jezebel (1938 with cast Bette Davis, Henry Fonda, George Brent), based on Brilliant scarlet dress (outrageous) the heroine wore, was actually Brown in colour. It was a well-deliberated move. Was this the story of red colour in dark dimly lit cave paintings of Paleolithic age? Could they have perceived black from the red, when both of which were extensively used. Paleolithic painters had several sources of black, such as wood charcoal, bone charcoal, manganese oxide, in addition to the tonal variations caused by the surface binding mediums like water, tallow, fish oil, eggs, wax etc. The hue variations were caused by the direction, and intensity of the lighting torch or fire used to see the paintings.

controlledburnuscg

Black is the ‘strongest colour’ (or in scientific language the most remarkable absence of all colours of the spectrum). It was used as draft line of the figure, for highlighting the silhouette of the figure, in few instances for defining the colours’ edges, for containing and bounding the running colours of low viscosity. Paleolithic painters used black (and also other colours such as ochres and red oxides) to shade the artwork for tonal effects. The tonal variations served the purpose adding a depth dimension, for emphasizing the important segments of the composition, and only in later periods for light shading. Light shading with subtle use black was to indicate the direction of the source and often to the root of the magical power.

carbon-476168_640

Carbon Black with high ash content

Carbon Black Pure

Black has been a great additive to tone up (or down) other colours. It, however, is a very strong shade tinter, even better than the whites available in early periods. Black, true to its nature, would reduce the brightness (visual impact) of the colour, compared with the addition of the white. Black added colours contribute depth to the colour. By the time of Iron age, the technique of adding black to vary the tones became much less popular. This was mainly due to the availability of multiple shades of ochres, oxides, etc. Blacks of different origins were added to whites of various types (such as calcium carbonate, barytes, gypsum) to achieve vast range of greys for use in mural paintings.

Red Black combination in Cave Art > Reproduction of a bison of the cave of Altamira Wikipedia image by Author Rameessos

The most difficult part was how to reduce or alter the tonal quality of black? Addition of white reduced it to grey shade, a completely alienated entity of black. In painting, the lightness of a shade was adjusted through mixture with white or black, but now by adding a colour. This was done first by using black of different origin, than by mixing very dark colours such as red oxide, black iron oxide, dark amber, and by adding low opacity ‘white minerals’. When yellows, reds and oranges are mixed with small amounts of black, it can cause a change to very a different shade.

Greys by avoiding the Black >> Gare Saint Lazare, 1877 Claude Monet (1840–1926)

Blacks, greys and other shades shift with the addition of black, often to a level that scared many seasoned artists and crafts-persons. The scare was more forbidding due to the metaphoric association with Gods, human behaviour and varied perceptual interpretations. Blacks of all origins, however, had one positive advantage that this was non fading or non destructible colours. Their tinting strength was fairly good and the perceptible shade was just ‘black’ with very few sub-variants. But its effect on other colours after mixing or through sheer proximity was extremely profound.

Impressionists avoided use of Black > Auguste Renoir – Dance at Le Moulin de la Galette

Art teachers, have been telling their apprentices, juniors and students to keep away from black. The same advise still holds true even today. If you are an interior designer, architect or builder, do not play around with black, unless you have the capacity for course correction or complete redo. Blacks are very opaque, and have a very high tinting strength, so a small amount can cause devastating effect. The small amount is very ill-defined and difficult to measure a term, and thoroughly mixing it into a larger mass without industrial equipment, an impossible task.

rosa-1911660_640Artists can mix few darker colours and get away with a ‘black’ like effect such as ultramarine blue and burnt umber can do it. The impressionists remained away from black, and preferred to devise the ‘black effect’.

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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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COLOURS -Perception and Expression

Post 356 –  by Gautam Shah 

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Colours have two relevancies. Some consider colour perception as biological phenomena, common to all human beings. Others perceive colour to be variable with social and a cultural facet. The social and cultural affectations of colour are observed in linguistic, ethnic, and aesthetic expressions.

Colouring_pencils

Perception of a colour, even if, a biological phenomena, one needs to convey that experience, usually by specifying the Hue and Tone of the colour. This may be done by comparison to some other colour of near hue and tone, and also by naming it in distinctive way.

Rangoli,kolam,chennai,Tamil_Nadu382

Nearly all languages unambiguously describe the black and white. Such unequivocal terms exist for few other colours, but not all shades. The third definitive term is for Red and fourth term could be either Green or Yellowbut not both simultaneously. The fifth definition may include either the Green or Yellow (excluded from fourth choice). The next, seventh descriptive choice is Blue. Other preferences in the choice sequence are for Brown, Purple, Pink, Orange, Gray.

Additive and Subtractive colours

Fluorescent_minerals_hg

Colours definitions other then these (11 or 12) common terms across different languages are more likely to be comparative idioms such as reddish, irrational value judgements like darkie or lighter, cool and warm tones. Metal and many materials have direct colour associations such as gold, silver, ash, orange (tangerine), KumKum (vermilion red), Turmeric (Haldi), etc.

Kumkum_By_Anis_Shaikh_31

The variations in colour terms across regions (cultures-languages) pose a different picture. In spite of scientific spectrum definitions, the cultural recognition and acceptance do not match.

Mountain-spring-redwhite

There was virtual lack of colour terminology in Homeric Greek literature, but it does not mean the Greeks could not perceive the colours as we do it now. We can now differentiate and define nearly 2.4 Mn colours. To distinguish a specific colour one needs to reference it in terms of hue, saturation, luminosity of the light, and context (contrast, background, reference -mental recall or spectrum definition).

Colour tonal variations Wikipedia Image by Phlake at en.wikipedia

We perceive colours and talk about it in entirely different context. We express colours through objects, surfaces, paintings, scenes, nature, fire, water, reflections, shadows, television, films, and other media. We also perceive colours with light and shade, textures, gloss, patterns, perspective, angle of vision, silhouette, visual aberrations and make-believe effects. In each case our connection with the colour is personal, and to recollect and replicate that experience into a scientifically coded vocabulary is difficult.

“The intensity of a spectral colour, relative to the context in which it is viewed, alters its perception  a low-intensity orange-yellow seems brown, and a low-intensity yellow-green looks  olive-green.”

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ARCHITECTURAL COATINGS -beginnings of OIL PAINTS

Post 337 –  by Gautam Shah 

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640px-A_Boyar_Wedding_Feast_(Konstantin_Makovsky,_1883)_Google_Cultural_Institute

The art of Oil painting developed in Europe in the late Middle Ages. It was widely accepted as a better art medium, as it was easier to work with and allowed a greater variety of effects in comparison to the (than available) other media, like encaustic paint, tempera, water colour, fresco, etc. Oil painting dried relatively slowly with little change in colour. Tones are therefore easy to match, blend, or grade, and corrections easy to make. With this medium the painter was not limited to linear brush strokes, but could apply paint in glazes, washes, blobs, trickles, spray, or impasto (textured effect). The painter was no longer restricted to a prearranged design, as the slow drying system allowed change, improvisation and over work. Rich effects were possible with colours, tonal contrasts, and chiaroscuro (shading). Jan Van Eyck, a Flemish painter in early 15th C. explored the oil paint as medium to work over the tempera style of paintings. The Venetians took it the further with oil painting on canvas.

Women of Algiers Oil painting on Canvas 18 C

Alchemists shop with Concoctions

Early oil paints were made by modifying the drying oils like walnut or linseed with natural gums such as amber, copal, pine-rosin, etc. The oils were cooked, or exposed to air and sunlight. But later, cooking was conducted in closed kettles under pressure and in absence of oxygen. These ‘stand oils’ were modified with natural gums, resulting in viscous substance. The viscous substances were reduced (diluted) with turpentine.

Johannes Vermeer, The Milkmaid (1658–1660) Oil Paint

Modified drying oil mediums were found to be good for wood surfaces, unlike the tempera colours. The grains and texture of wood surfaces helped in binding the medium. It was also realized that the medium should have a better body (high viscosity compared to pure oil materials) and drying properties, otherwise would run (drip down).

Safflower oil as paint medium

art_supplies_artist_art_supplies_creative_color_paint_pastels-816166.jpg!dLéon_Bakst_-_Bathers_on_the_Lido._VeniceOILS AND OLEO-RESINOUS BINDERS

OILS: Vegetable oils and animal fats are the oldest binders known to man, some of which are still in use today. The suitability of an oil as a film forming substance depends on the highly unsaturated fatty acids. To make raw oils usable, three treatments are carried out 1. alkali refining to reduce the acidity and improve the colour, 2. kettle bodying -heating oils for a prolonged period at high temperatures to increase the viscosity and polymerizes it, 3. blowing air or oxygen through oil at elevated temperature to increase its oxidation.

Types of Oils: Drying oils (Linseed oil, Tung oil -china wood oil, Dehydrated castor oil), Semi drying oils (Safflower oil, sunflower oil), and Non drying oils (olive, castor, cotton seed, coconut oil). For coatings drying oils and some semi drying oils are commonly used.

Flax plant to Linseed oil

Oils have been treated with many types of processes and substances. This included metallic salts. There were many problems with oil modified film forming substances. There was colour darkening of coating on ageing. It was not possible to create long lasting lighter colour shades. Over oxidation made the film very weak. Presence of natural gums made the film tacky in moist weather. The process of polymerization was not clearly understood.

resin-2290750_640OLEO-RESINOUS BINDERS: These substances are often combined with oils, bodied oils or their resins. Rosin is a low-cost resin derived from sap of mainly Pine trees (abietic acid). It is neutralized with lime (to form calcium Rosinate), glycerin (ester gum) or penta-erythritol (penta). These substances are now used in low cost paints and varnishes, or as cost effecting additives. Coumaro-indene (cumar) resins are derived from coal tar naphtha, and are used in leafing aluminum paints and other low cost systems. Phenolic resins are produced by reacting synthetic phenolics or phenolic compounds (cashew nut shell liquid) with formaldehyde.

Resins oozing out of a fresh cut in a tree

Gum Arabica

The technology of oil coating, in spite of its many drawbacks was very popular. It first came into being as the art media, but soon began to be used extensively in upgrading the interiors of mansions and palaces. It was the beginning of oil based architectural coating system.

Oil Paint work on Gopuram (Gate structure) of a Temple Chennai India

With the onset of industrial revolution the use of iron and ferrous alloys became extensive. Not only coating materials in large quantities, but for specific surfaces were now required. Rusting was a major problem with metal surfaces. Many protective coating systems were developed.

Semporna Sabah Multicoloured longhouse

During world war II, availability of natural oils such as linseed, castor, etc., which were of Asiatic and transatlantic origin, was affected. At the same time several petroleum-based products and derivatives began to be produced. These prompted research on non oil resins. Such chemically polymerized resins had faster drying time, better toughness, finer gloss and superior colour fastness, then heat bodied mediums. Polymeric resins both, thermo-plastic and thermo-setting varieties were produced.

ALKYD RESINS

Alkyd resins first came into use in the 1920s. These first alkyd resins (first polymerized polyester resins) were merely the reaction products of phthalic anhydride and glycerine. These products were too brittle to make a satisfactory film. The use of oils or unsaturated fatty acids in combination with the brittle alkyds resulted in the air-drying coatings which revolutionized the coating industry.

Architectural coatings

Alkyd resins form the basis of most of the commercially available glossy paints, flat paints and primers. These are produced by reacting drying and semi drying oils with a phthalic anhydride (acid), glycerin and penta-erythritol. Resins which have smaller proportion of oil -called short oil alkyds, or have oils of semi drying type, are used in baking finishes or as plasticizers. While long oil alkyds are used for air drying finishes or GP Enamels. Typically a long oil alkyd will take longer to dry out but may have higher strength, and a short oil alkyd may require baking to aid the drying.

Synthetic resin manufacturing through a complex plant

A variety of alkyds are produced by modifying them with other polymeric compounds. These modifiers are like: Rosinated alkyds, phenolated alkyds, styrenated alkyds, silicone modified alkyds, epoxy modified alkyds, acrylic modified alkyds, vinyl-toluene modified alkyds, and urethane alkyds.

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