Post 357 – by Gautam Shah 


Large number of items and components are available in ready to use state with a suitable finish. These products require no extra treatment or coating, before or after the installation. The industrially finished items are class apart from finishes applied on a site, after assembly or erection.

An industrial plant offers streamline production system, in a batch or a continuous fashion. Industrial plant-based surface finish is a process integrated with production and highly articulated one. It is invariably conducted in a controlled environment and observance.


Two men on a platform painting Hull of a ship Himalaya >Wikipedia Image by Australian Maritime Museum

Site applied surface finishes, substantially consist of architectural coatings, and are multi surface applications (general purpose or GP systems). Other on site applications, but not forming part of architectural range, include Road marking paints, Marine paints, and re-application systems. On a site coatings are employed in a wide range of weathers and in open environments. Architectural coatings, for ‘drying’, rely mainly on moisture evaporation, induced polymerization, and in few instances on catalyst curing (popularly known as ‘two-pack’) systems. Architectural coatings are applied, chiefly on masonry, and than to lesser extent on wood and metal surfaces.


Prez Obama and wife help paint Habitat for Humanity site, Washington, Official white house Photo-stream Image by White House (Pete Souza) / Maison Blanche (Pete Souza) 

Industrial finishes are very specific systems, formulated for a particular substrate, object shapes, sizes, pre-treatments, method of application and drying or curing cycles and schedules. As a result, complex surface finish technologies can be used. Industrial finishes offer qualitatively a far superior finish compared to any site-based system.

Dipping treatment for Automotive industrial coating

An industrial coating, forms a very small and often a negligible part of the total cost of the product, its failure in any form destroys the entire value of a product, and manufacturing company’s reputation. Defects of industrial coatings, if any are realized after the product has reached the consumer. Remedial measures are impracticable, and it entails a recall of the product from unknown or far off locations. Industrial coatings must be continuously upgraded. Otherwise, a technologically superior product gets rejected from the market due to its aesthetic and sensorial appeal.

White-goods Consumer appliances

Industrial finishes are generally low in pigments or extenders and high to medium ‘build’. Quality of the finish is largely determined by the type of film forming mediums used. Many industrial finishes are formulated for baking-drying to achieve a hard, stable and durable finish. Amino and epoxy resin coatings dry by catalyst action. In powder coatings thermo-setting materials are heat liquefied to set. Industrial coatings also include air drying, partially air drying & low temp baking, stowing, radiation-curing, solvent-evaporating, oxygen polymerizing (oxidizing) heat polymerizing and catalyst curing, thermo plasticizing carbonating, systems. Industrial products receive pre-treatments to make their surfaces suitable for a single system of coating and through single application. The pre-surface treatment include moisture conditioning, rust inhibiting, galvanic control, texturing and levelling of the surface, etc.


Wikipedia image > Image by


Industrial finishes can be classified as:

  • Traditional systems  

These are based on alkyd resin technology

  • Lacquers

High molecular weight resins, such as vinyls, acrylics, chlorinated rubber, etc. that are dissolved in a solvent and do not undergo any chemical change on drying.

  • Dispersion mediums

  These are dispersions of convertible system.

  • Latex systems

Contain resins dispersed in water or other liquid that do not dissolve them. Resins are invariably high molecular weight polymers.

  • Chemically curable systems

These are made of thermo-setting resins of low molecular weight such as epoxies or urethane, that in the presence of a chemical or catalyst complete the bond formation.


Today industrial coatings are also seen in terms of environmental compliance, or the pollution hazard they can cause. The total volatile organic component, VOC. criteria is a factor that defines the worthiness of a coating system.

Water borne coatings: 

These are made from emulsion, water reducible and aqueous colloidal dispersions.

High solid coatings:

High solid coatings are frequently based on conventional polymers but with low molecular weight.

Powder coatings: 

These are based on thermoset and thermoplastic resins with pigments, fillers and additives such as hardeners and flow agents.

Advantages of Industrial coatings: Items which are difficult to coat due to their shape, size or location can be efficiently coated in an industrial set up. Items with sharp corners and edges can be coated evenly. Certain types of pre-treatments, which are not possible on a building site can be carried out at plant level. Materials and methods which are difficult to handle, or are normally hazardous on a site, can be employed at plant level. Industrial application of coating is very efficient and controlled so very thin film thickness can be achieved, and lot of wastage on account of drips and over sprays can be eliminated. Many application techniques, tools, equipment can only be used at plant level set up.

Painting booth

Industrial Coatings include White goods (consumer products of chiefly white-coloured, but not always; such as refrigerates, washing machines, ovens, gas stoves, geysers, fans, air conditioners); Consumer electronic products such as computer and server cabinets; Industrially produced furniture such as chairs, cabinets, tables, partition systems; Vehicle products such as cycles, scooters, bikes, cars, trucks, buses; Extruded or formed Long products such as steel, aluminium and composite sections, and pipes; Besides these there are several applications where clear (pigment less) or non toxic coatings are used such food containers, toys, etc.


COLOURS -Perception and Expression

Post 356 –  by Gautam Shah 


Colours on Roofs 1

Colours on Roofs 2

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.


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.


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


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.


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.


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.”


Louis Anquetin, a French artist commented in his book that old masters’ palettes were small and set with a few, almost nondescript-looking colours, out of which they made jewels on their canvases. The contemporary artists’ palettes were enormous by comparison and set with a dazzling array of colours, and they produced drab paintings.

Colours on Temple Gate Gopuram India