Page 176 - Reliance Foundation School Koparkhairane - School Magazine - Zenith 2020-21
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Dyes make our lives colourful.                                                                                         These are the oldest dyes and are commonly used for dying of
                                                                                                                                  textile and other substances. These are water-soluble dyes and
           “Life is like a rainbow. You need both rain and sun to its colour appears.” By unknown.                                are  easy  to  use.  Another  example  of  natural  dye  is  Tyrian

           Tina got a new pink colour school bag as a birthday gift. All her friends were excited about her new school            purple, which was extracted in very small amounts from the
           bag. In school students were having different colour bags and other stationery materials. They were happy              glands  of  a  snail,  Murex  brandaries,  indigenous  to  the
           sharing colourful material with each other.  Seven colours “VIGBOYR” make our life colourful and happy.                Mediterranean Sea. This dye was called 'royal purple' because
           Human emotions are also expressed in the form of colours. Nature gives us a variety of colours and shades in           it was worn by royals, kings, priests etc
           form of flowers, colourful food items, colourful insects etc. They are called natural colours. All above of            Lycopene is a common example of natural dye present in tomatoes and other vegetables. This compound is
           these is our eyes are please when we see a rainbow in the sky. Nowadays we use colours in form of crayons,             responsible for giving red-yellow colour to the substance.
           watercolour, acrylic colours, etc. These all are synthetic colours or the colours which are prepared in a
           laboratory. These are not obtained from natural sources like plants, leaves or animals. Colours make our life
           beautiful.
           Colours  are  organic  and  inorganic  compounds.  These  are
           called dyes. Dyes are chemical substances used for colouring
           purposes. Which is your favourite colour? Some of you may say
           blue, pink, black, orange etc. Have you ever wondered when
           and how these colours are prepared? From when are we started
           using colours? History is not my favourite subject and why                                                             Synthetic dyes
           should I read it? History is not just limited to pre-historic man,                                                     Dyes prepared in the laboratory are called synthetic dyes. In 1856, an English chemist William Henry Perkin
           copper age, metal age, or just chronological order but here we                                                         was involved in the synthesis of antimalarial drugs. Accidentally he discovered 'Mauve' purple colour.
                                                                                Fig.1: Mixture of all colours
           would read about the discovery and development of colours.  https://www.pictowall.co.uk/wallpaper-designs/colour/
           In this article, we would read about natural and synthetic dyes.

                                                                  Dyes are organic compounds more commonly
                                                                  made  up  of  carbon-hydrogen  (HC)
                                                                  combinations. Traditionally dyes obtained from
                                           Fig. 2-The heterocyclic dye
                                          known as indigo is a naturally   natural  sources  like  plants,  animals  etc  were
                                          occurring compound that can
                                                                  used  for  dying  or  colouring  purposes.  Dying
                                          be obtained from plants in the
                                              genus Indigofera.   of  textile,  paper  etc  is  found  since  ancient
                                             A to Z Botanical Collection/   times. Earlier people use natural dyes, obtain
                                            Encyclopædia Britannica, Inc.
                                                                  from plant or animal sources. Literature shows
                                                                  the  usage  of  natural  dyes  by  Egyptians  4000
                                                                  years ago.

           Indigo and Alizarin are the oldest natural dyes. Alizarin is a red dye extracted from the roots of the madder
           plant, Rubia tinctorium. Other red dyes were obtained from insects. These include kermes, obtained from                           Fig.4- Perkin portrait                   Fig.5- Mauveine in the historical collection of dyes
                                                                                                                                                                                          of the technical University of Dresden
           Coccus ilicis (or Kermes ilicis), which infects the Kermes oak, and cochineal, obtained from Dactylopius
           coccus, which lives on prickly pear cactus in Mexico.                                                                  This revolutionised the dye industry. Many attempts were made to synthesise other dyes. These dyes earn
                                                                                                                                  importance because of their properties like stability to high temperature, retaining ability, no action of
                                                                                                                                  acidic substances. Over decades dye industry has expanded to a wide area. It has found applications in a
                                                                                                                                  variety of areas like textile, food, polymer, metallurgy etc.
                                                                                                                                  References:

                                                                                                                                  1) https://www.bbvaopenmind.com/en/science/research/mauve-the-history-of-the-colour-that-
                                                                                                                                       revolutionized-the-world/
                                                                                                                                  2) https://www.britannica.com/technology/dye
                                                                                                                                  3) https://nptel.ac.in/content/storage2/courses/116104046/1.pdf
             Fig.3-Structures of Organic dyes
                                                                                                                                  Pratiksha Rajadhakshya



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