What Causes Color?

• Chromophores are the part of a molecule responsible for the colors we see. When a molecule is exposed to light, the chromophore causes the molecule to change shape. In many pigments, including fabric dyes, the chromophores contain alternating single and double bonds. Light excites electrons, which move between the orbitals created by these bonds.
  
  

How Does Bleach Interfere With Color In Fabric?

• Bleach usually works by either oxidizing or reducing. Oxidizing bleaches break the chromophore's chemical bonds, altering the structure of the molecule so it does not absorb light within the visible spectrum. A reducing bleach also alters the molecule, but it does so by changing the double bonds into single bonds. The most commonly used bleaching chemicals are chlorine, sodium hypochlorite, hydrogen peroxide and calcium hypochlorite. Sunlight may also create enough energy to disrupt the bonds of a chromophore, and sun exposure can bleach paint and clothing.
  
  

Other Uses of Bleach

• Bleach is used not only in the textile industry but also as a cosmetic for whitening skin, teeth and hair. Different types of bleach are used for different applications, such as manufacturing paper and bleaching white flour. Bleach is also commonly used as a cleaning agent, since it destroys a wide range of bacteria and micro-organisms.