YELLOW

Exploring the meaning of YELLOW

All the world over, yellow is associated with the sun and its life-giving warmth.Yellow also stands for caution, and it’s used for traffic warning signs and traffic signals in nearly every country. Yellow is optimism and the cheerfulness of a sunny day. The colour yellow also relates to acquired knowledge ~ learning. It is the colour which resonates with the left or logical side of the brain stimulating our mental faculties and creating mental agility and perception.

Bringing sunshine to your life?

The colour yellow loves a challenge, particularly a mental challenge!

It is such a happy colour that it is no surprise to me that it’s energy seems to encourage communication. Yellow is the colour of the gamer and writer alike, all working and communicating on a mental level. But it is the scientist, checking all angles before making a decision; methodical and decisive.  However, this analytical behaviour can make you more critical both of yourself and others.  

Yellow is also the entertainer, the comic, the clown.

It is also related to the ego and our sense of self worth, to how we feel about ourselves and how we are perceived by others. 

"How wonderful the colour YELLOW is. It stands for the sun". ~ Vincent van Gogh

Yellow in the natural world

Where it appears in nature, bright yellow is hard to miss. It is one of the most luminous of colours and on its own stands out against all contrasting colours. But YELLOW too has also evolved as one of the most important components of WARNING COLOURATION (aposematism). This colouration is designed to prevent attack by warning predators off. Often the colouration warns that the animal is venomous or unpalatable.  So the brighter and more conspicuous the organism, the more toxic it usually is.

However its not quite as straight forward as that! Nature is famous for using effective colour combinations! Yellow alone does not signify a warning. But against a contrasting BLACK colouration, the YELLOW stand out in a much more luminous way against any green foliage. These colours do not easily blend into any natural background. 

IN the battle between predators and their prey, many prey animal have evolved mimicry …. They LOOK LIKE an animal that might be dangerous or venomous but they aren’t. It’s a kind of Warning colouration by Proxy! 

AS human we have adopted this warning colouration in many road warning around danger? And Hi Viz, yellow and black jackets worn by Traffic Police are clearly visible from a considerable distance away. Pedestrian crossings too! Yellow is the most highly visible of all colours which is why it is used for pedestrian crossings. Take note of the crossings which are marked in white – they are less easy to see than those marked yellow, particularly on wet and cloudy days.  

Natural Yellow Pigments .....

Colouration in butterflies and moths

These colours come from two sources. The first are pigmented colours which are simply ordinary chemical pigments that absorb certain wavelengths of light and reflect others. The wavelengths that are reflected are the colours that you’ll see. An example would be that the shades of brown and yellow seen in most butterflies comes from melanin, the same pigment that tans your skin when you sit in the sun. When light hits the object it absorbs all the colours except the shades that create brown or yellow.

The second source of colour is called ”structural colour’ and results from the specific structure of the butterflies’ wings. Butterfly wings are covered by lots of little scales which layer on top of each other and are separated by little pockets of air. Because of this structure colour appears to shimmer and shift as an observer moves is actually a light effect known as IRIDESCENCE. Iridescence occurs when light comes through transparent multilayered surfaces and is reflected more than once. It’s as if all the reflections become concentrated creating a really vibrant display that catches your eye!

Yellow colouration in plants

Reflection of light waves

It’s sometimes feels hard to remember that we only see the colour of anything because the pigment causing it is REFLECTING the Yellow wavelengths of light back out to us .. to our eyes!  These pigments absorb all other wavelengths. The pigments that behave like this in flowers are called CAROTENOIDS and yes they also make carrots look orange! 

Leaves on trees also contain carotenoids but also produce xanthrophylls. The predominant colour in leaves is clearly GREEN, caused by the presence of CHLOROPHYLL. 

As leaves age and become less efficient at doing their job of making sugars, the leaves stops producing Chlorophyll and this allow other pigments which are also present in the leaves to show up.  This also happens when the plant is short of Magnesium which it needs to make chlorophyll. 

…. AND ABOUT BANANAS

We all know that Bananas are green when they are picked. This is because of the chlorophyll in their skin cells! However, once picked, they begin to ripen: hormones in the bananas are produced with convert amino acids into a gas called ethylene. Ethylene causes all fruit to ripen. Ripening in bananas in which the colour texture and flavour changes is caused by enzymes. The green chlorophyll supply is stopped and the glorious yellow colour of the carotenoids replaces it. Left too long, of course your bananas go brown but of course they are still great for making banana bread.