We’ve written several articles about clouds. We’ve seen what clouds are, why they are white or grey. This has led to a question. When I paint and mix the colours why do they go grey not white?.
I’ve had a great start, in fact much more than a start, with this question from a fellow WordPress blog owner – quirkyintrovert (there is a link to her blog at the end of this post.)
I didn’t have a clue where to start, what to search for, or what title to give the post! The jury is out on the title!
What is Pigment
pigment – /ˈpɪɡmənt/ – noun
- A substance occurring in plant or animal tissue and producing a characteristic colour, such as chlorophyll in green plants and haemoglobin in red blood,
- Any substance used to impart colour,
- A powder that mixes with a liquid to give a paint, ink, etc.
Reflection happens when incident light, (incoming light), hits an object and bounces off it. Very smooth surfaces, like mirrors, are very good reflective surfaces. They reflect almost all incident light.
The colour of an object is the wavelength of the light reflected, when all other wavelengths are absorbed.
Here, colour, is the different wavelengths of light in the visible light spectrum as understood by our eyes.
The physical and chemical composition of matter determines which wavelength (or colour) is reflected.
Why Paint Looks a Certain Colour
Paint appears a certain colour because the pigments in it absorb certain wavelengths of light and reflect others.
For example, the pigment in red paint:
- absorbs the visible wavelengths – Orange, yellow, green, blue, indigo and violet.
- and reflects the visible wavelength red.
So, when you mix all your different coloured paints together, you get clumps of pigment which absorb all the visible light wavelengths.
This is because all the light is absorbed, none is reflected, and the resulting “colour” appears black.
Does Light Really have Colour?
It’s important to remember that light isn’t coloured.
Instead, it is a wave which exists in different wavelengths or frequencies which the eye and brain interpret as different colours.
When light strikes receptors in the eye, it sends a chemical signal to the brain, which interprets it as a colour.
That is why when all the different wavelengths of light in the visible spectrum strike the eye’s receptors, it is perceived as white.
Do Objects have Colour?
Technically, objects don’t have a color. The color that an object appears to us is as a result of the interaction of light and the atoms that the object is made of – whether it is reflected or absorbed – and the reflected wavelengths interacting with receptors in the eye.
A Note to You and Me
Here is the link for quirkyintrovert, who kindly explained this so well. I would have struggled without it! Thank you so much.
Thank you so much for reading this article. Here are links to our cloud posts: