Sidey’s weekend theme this week: Colours. My first response when I read it was along the lines of: “Fly the flag”, “nail your colours to the mast”, etc. that is SAY WHO YOU ARE and no cheating, but then Kate has created a wonderful post around this theme, so I moved to plan B. Or, RGB, RYB, and even MCYK. Read On. This is about beauty and the wonder of the RAINBOW.
Isaac Newton is often credited (wrongly) with first showing that
separates into –
all the colours of the rainbow.
[Newton actually showed that they could re-combine.]
[Picture from Squidoo, Rainbow Science]
The energy in the e.m. waves travels everywhere, through space. Like white light before it meets the prism, it is not separated. But, when it meets something, depending on what the something is, glass, wall, even you and your new shirt, then it separates, and some can be absorbed, some reflected, some can pass through. Which wavelength goes where depends on all those atoms and molecules we can’t see and how they are arranged.
This logic sorts out one of those muddles I used to hear from pupils and students.
WHAT ARE THE PRIMARY COLOURS?
Red, YELLOW, Blue, according to the RYB, the way we all learn to mix colours in primary school art class.
or Red, GREEN, Blue, according to Maxwell and physics.
There is no muddle. [except for spelling color/colour]
If light is arriving somewhere, that is hitting something, then some colour will be absorbed, or some will pass through, some will be reflected, the mix depends on the atoms in the something. The colour of the light we actually see is subtractive. My shirt does not make colour. Pigment or paints do not make colour. What they do is reflect back just part of the total spectrum, so we see only that part. When we mix subtractive colours, the primary colours are indeed
RED YELLOW BLUE, the RYB.
And actually, the primary colours do not have to be RGB, they can be Magenta, Cyan and Yellow – this is the MCYK system used in color printing.
But, if the light is being produced, energy being EMITTED from a source, this is additive, and Red Green and Blue are the primary colours.
If RED shines out from one source, GREEN from another, and BLUE from a third, the different sources mix together to create white, or clear light. RGB.
Computer monitors and televisions are the most common form of additive light, while subtractive color is used in paints and pigments and color filters… Another common use of additive light is the projected light used in theatrical lighting, such as plays, concerts, circus shows, and night clubs… Additive color is a result of the way the eye detects color, and is not a property of light.(from Wikipedia)
Talking of subtraction and addition, does the logic and science of colours add or detract from the beauty of the rainbow, or the pleasure felt when light catches the edge of a mirror or a crystal hanging in the window, and suddenly there are little rainbows dancing over the walls?
I love both, the logic and the beauty, together they are more. One of my all-time favourite poets, John Keats, disagreed. At least in one poem. Others agree, of those, Richard Dawkins, with whom I often agree, is not my favourite author (he does try, in both senses of that word). I found a post called Battling Rainbows.
Science and logic are not separate from emotion and response to beauty in being human. I love both.
Light, colours, rainbows, logic, understanding, beauty.