We perceive color as a result of light interacting with our eyes; the properties of physical objects can alter the way they absorb, reflect and emit light, changing the way we see them. Color is everywhere – including in chemistry. A chemical gets its color by electrons absorbing energy and becoming excited. That excitation absorbs wavelengths of light; what we see is the complementary color of the absorbed wavelengths.
Colors have a huge impact: they are fundamental in art, photography and fashion, they can affect our mood and productivity, and they can even be used in forensic science in the analysis of chemical composition.
National Chemistry Week 2015 focuses on the theme “Chemistry Colors Our World.” To celebrate the contribution researchers make through the work they publish in Elsevier’s chemistry journals, we have put together a collection of articles that showcase the spectrum of research in this theme. The articles cover everything from analyzing powder quality using color to identifying mystery painters.
From the yellow pigment of silkworms to the red dust of Mars …
Chemistry can help improve manufacturing techniques. Some wild silkworms produce silk that is naturally colored; a mutant of the domestic silkworm, B. mori, can spin yellow cocoons. This naturally colored silk is potentially valuable if it can be processed without damage and fading. A Dyes and Pigments categorizes the yellow pigment to understand better how the silk could best be processed.
Research in chemistry can also tell us what’s happening on other planets. Mars gets its red glow because of a thin layer of oxidized dust. Despite decades of attention, its geological and climatic implications are still a matter of debate. Research published in Earth and Planetary Science Letters reveals hydroxylated ferric minerals may have a prominent role in the production of the dust.
Back here on Earth, human activity can lead to towns and cities being significantly warmer than surrounding areas. To tackle these urban heat islands,” cool roofs that reflect the sun’s rays can reduce the temperature. A study published in Ceramics International presents a new generation of colored glazes, which have the potential to perform better than existing materials.
Colors aren’t just functional – they’re also aesthetic. Art galleries all over Europe have collections of paintings they don’t show publicly because of their doubtful attribution and dating. A study published in Applied Clay Science shows that looking at the presence of clay-based materials in paintings can distinguish those from Italy and central Europe.
These and many other studies show the spectrum of research being done in chemistry to improve manufacturing processes, reduce our impact on the environment and give us a glimpse into the past.