Sources of Natural Colours in Natural Finishes
We all have our preferences of colours in the Finishes of our Wall Plasters and Floorings. There are unlimited colours in Nature that can be used in our Buildings, instead of modern health-hazardous paints and coatings.
With the selection of colour, one needs to look at its absoprtive, emissive and reflective property. We can play with it creatively to give different textures and finishes. One needs to check over the strength of colour and its durability over sun,humidity and rain before deciding. Now lets look at some Sources of Natural Colours for our buildings.
Picture Coutesy : Bill & Athena
Picture Coutesy : muirne katedineen
There are many common minerals used from ancient times to produce vibrant pigments. Some examples are Oxide minerals, Azurite stones, Carbon, Chromium, Titanium, Lead, Cobalt and Copper.
Ochre Colours or Oxide Colours are the most important of the mineral colours that we still use today. In many rocks containing metals, their iron content gets "oxidised" producing beautiful hues, thus naming them oxide colours. These Ochres are a composite of Hematite, Limonite, Clay and Iron Oxide varying in percentages. The deposit of ochre minerals differs in every state of India, with Western India containing the most.
Ochres produce strong and durable shades due to its content of iron oxides and other metals. They can be used for exterior finishes to withstand rain and sun, and can also be polished to give shiny appearances.
Umbers are Reddish-Brown coloured ochres with manganese oxide content.
Siennas are Yellowish Brown pigments containing both iron and manganese oxide.
Ochres are Clay coloured with different colour ranges from yellows, to oranges and browns with the varying of iron oxide content.
Among the many ochres, the red ochre is the most familiar, containing red oxide which has habitual uses in the Natural Finishes. Oxide minerals are given different names according to their metal content. With the use of different oxides, gives different colours.
Chromic Oxides give a Chrome Green Colour.
Lead chromite gives Chrome Yellow.
Cadmium Sulfide gives Cadmium Reds and Yellows.
Cobalt Oxide gives Cobalt Blues.
Mercuric Sulfide gives Vermillion Oranges and Reds.
Burning the oxides can also produce even different shades and hues of the pigments.
Apart from Oxide colours, many other different rocks containing metals can be used to produce natural and long-lasting colours. Stones like Lapis Lazuli, Azurites were ground to produce blue hues. Galena obtained from Lead ore can be heated to produce ranges of whites to reds. Malachite and Chrysoprase stones are sources of green pigments.
Lapis Lazuli Powder
Mud based Finishes
The colour of the mud is the most dominant in Mud-Based Finishes. Earth contains millions of hues of reds,browns,oranges,blacks and whites. Every 100 feat of earth has different soil properties and colours. One can utilise the natural earthy shades of the mud to produce different possibilities.
The shades of the Mud can be tweaked a little by the addition of additives like cow-dung, charcoal,etc.
Picture Courtesy : Bill & Athena
Picture Courtesy : Sigi Koko
Lime Based Finishes
Jodhpur, the blue city, comes to be identified by its trademark mild blue tones of their houses. This is a lime-based paint with copper sulphate minerals and indigo to give it the heat-reflecting coating as well as insect repelling qualities.
Limewash or Lime plasters or Flooring were the staple finishes of India, till a few decades back.
Lime has the tendency to nullify any natural pigments given to its white. Hence, only mild natural colours are achievable with Lime plasters mixed with mud. Limewash has good reflective property and can also keep termites and insects at bay.
Picture Courtesy : Sigi Koko
Picture Courtesy : Muirne Kate
Colours exctracted from plants and animals can be used in the interior finishes of the buildings as most of them have a tendency to fade with sunlight exposure.
Plant Extracts of different colours can be used like Flame of the forest, Turmeric in Lime based finishes. Oils, waxes,resins can also used in the final coating of the finishes. Many different plant roots, barks can produce different colours. Literally, the sky is the end to create different pigment possibilities.
Animal Sources can also be used like Cow dung(with mud) to provide darker shades of finishes.
There are even Milk based paints that uses casein to paint the final coats of plasters to provide a shiny and artistic look. Curd and eggs are a main ingredient in the traditional Chettinad Plaster.
It is really upto us to innovate and express ourselves through the charming medium of Natural Finishes.