h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

How do you make pink?

I was just thinking* about how to make the colour pink - and in the sort of child's paint set method I know I'd mix red and white - but I figure that can't work ordinarily for the **colour** pink in general, so it must be a diffuse sort of red, one comprised from all three light primary colours (hence white) but with just a predominance in red. Am I correct?




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*A little context: My mind wanders while I'm brushing my teeth - I was daydreaming about teaching a lesson on light, spectrums, colours etc - and in my head this became a lesson on rainbows - and covering notions of light going in straight lines,reflections, shadows etc - and I imagined asking a class what the colours of the rainbow were, expecting:

red and orange and yellow and green,
indigo, violet and blue

- which is how I learnt them, but I also know of a different version of the song which goes:

Red and yellow and pink and green
Purple and orange and blue

pink and purple replacing indigo and violet. and this is the form I most often here in schools.

So, in my head I heard myself objecting, but there isn't pink in the spectrum (as in when you split light in a prism) so why is it included in a song about rainbows?

BECAUSE (and here comes the explanatory part which prompted the above question) If you split white light into the spectrum, it can't be white light that is 'mixing' with red light to make pink.

So is the (2nd song) incorrect - and there is no pink in a rainbow or if there is pink in a rainbow - how is it being made/generated?

Clive.

A bit confuzzled and sleepy - if any of that doesn't make sense say so and I'll try re-phrasing it.

Oooo! Interesting question. I'll be happy to give it a shot.

I was disgruntled to have been taught primary colors wrongly in my schooling, but there is a better way that I have since learned! You know, the usual first thing we learn about color is that red, blue and yellow are primary colors. Well, yes and no. They are... but it depends on what you call "red", "blue" and "yellow". I can't believe I'm trying to explain this to a colorblind man, but I will foolhardily attempt it.

Now. Let us begin at the beginning.... everything we see is composed of light. This is true whether the light is seen directly from the source or reflected from surfaces. Sometimes the colors mix inside our heads, but it all comes down to basics of light frequencies and they way they are transmitted to our eyes.

Pure light from our sun is seen as white, and as you know, it can be split into a spectrum of colors that we know as the rainbow. Absence of light is seen as black.... or nil reflected light.

You're right about the apparent lightness or darkness of a color depending upon the amount of white light or absence of light "mixed in" to the hue.

Now, this may be difficult for you to completely understand, because you can't really see it, but bear with me. There are two major ways in which colors mix...

One is color mixed with light being transmitted directly to your eyeballs, which is called "additive color mixing". This system is used in things like your computer screen or television screen where values of red, green and blue primary light are mixed to form a vast array of colors, depending on the amount ADDED of each...

IN MIXING LIGHT:

Green + Blue = Cyan
Blue + Red = Magenta
Red + Green = Yellow
Red+ Green + Blue = White

The other way we mix colors is through a "subtractive" process. Same light is being used here, but now we're mixing pigments that absorb light and reflect back what's left over. Whenever you mix paint, or ink or watercolors the subtractive method is what you're using. We're most familiar with this from our earliest experiences with finger-paint.

IN MIXING PIGMENTS:

Cyan + Magenta = Blue
Magenta + Yellow = Red
Yellow + Cyan = Green
Cyan + Magenta + Yellow = Black*

*However, since there is no pigment on earth that is perfectly pure, equal amounts of Cyan, Magenta and Yellow will usually make hideous brown, or some sort of nasty, puke-colored gray. This is why, in standard, four-color, offset printing, black ink is used to deepen and strengthen the image.

Do you see the correlation between the two methods? They are the exact opposite of each other! Red and Cyan are opposed to each other on a color wheel, as do Green and Magenta, Blue and Yellow. In fact, if a photo contains an obvious cast of one of these colors, it is possible to correct the color balance by adding the opposite color! Just like magic.

Now, I've had scientist-types argue with me that there is no such thing as a magenta wavelength, only violet. Maybe so, but they are full of poo. I use magenta light constantly as an image technician/printer and I assure you that it is a necessary and basic component of nearly every photo, computer screen image, print or color page you own.

Magenta and Red are similar colors in the same way that Cyan and Blue are similar. Both magenta and red are called "red" in casual usage... although magenta is sometimes confused with violet or purple, it is actually more like an intense, hot pink. Red is closer to orange, but not orange, although it too contains a lot of yellow pigment when mixed subtractively.... but it is the color of primary red light. :P Are you confused yet? Cyan is closer to the color of the sky, whereas blue is deeper and borders on violet also. In fact, the most beautiful colors of violet emerge when pigment is mixed with a predominance of magenta over cyan.

How does this relate to the split of visible light as seen in the spectrum? Well, that's split in a linear way, whereas practical color application in the real world mixes in a more circular way, which is why we depict it with a wheel.

Now, how does all of this relate to pink? Well, if you are mixing pigments subtractively, then the truest pinks are mixed with magenta and white. A transparent watercolor paint can allow the white paper color to show through to soften the color.... or a lesser percentage of magenta ink is applied in printing to allow the white paper to shine through. Or, in the case of mixing opaque paint, simply add white paint to magenta paint to get pink. Red will also make a respectable pink when mixed with white, however it is more tinged with yellow. Red paint containing too much yellow may go peach when mixed with white. Adding a tiny amount of blue paint to magenta and white will make more of a lavender pink.

I think I may be losing you now.

One would never think that the subject of color is such a complex one..... it takes a single hour to learn the basics of color mixing in Kindergarten class, but a lifetime to understand the details. Happy learning to you, Clive.



I hope this isn't terribly badly explained.... it's late and I'm high on a PB&J sugar coma, but I'll be happy to try and clarify anything that doesn't make sense. I could go on and on. I guess you can tell that color is a special interest of mine.

PS:

For lack of a better system, color is described using different terms to describe different aspects of it....

Hue = the color. Is it red, purple... or is it blue?

Value = lightness or darkness. Is it pink, red, or maroon? All are values of the hue red.

Saturation/Intensity = Relative brightness of a color. This refers to how dusty or subdued a color is or how brilliant. Pure colors tend to be like a crayon box.... the same color with less saturation will be duller and more grayed down. Lime green is intense and saturated, whereas olive drab is exactly that.... but far more wearable.

Hope that helps.

PSS:



Pink is also mixed in varying shades with light, such as with a computer display....all by adding more white light to the mix, but balanced towards a predominance of red and blue light, less green. In other words, a mix of full-on phosphors, with some green light taken away, will produce a tint of pink (pale magenta). By the way, red works too, it's just a different hue of pink. Go ahead, try it...

http://colormixers.com/mixers/cmr/

example:

R 255
G 200
B 255


Links I should have added above....

http://en.wikipedia.org/wiki/Additive_color

http://en.wikipedia.org/wiki/Subtractive_color

Sorry about them being the competition.

PSSS:

"but I figure that can't work ordinarily for the **colour** pink in general, so it must be a diffuse sort of red, one comprised from all three light primary colours (hence white) but with just a predominance in red. Am I correct?"

I should have cut to the chase and told you immediately that you were dead right.... pretty awesome deduction for someone who can't actually see the color. You never cease to amaze me, Clive!



Keep in mind that "pink", like most color names, is not terribly specific. Pink comes in a dazzling array of somewhat similar hues, but they have differing values and intensities. The reason I bring up magenta is that I feel it is at the central point of what most people would think of when they visualize pink.... including the purest form of magenta light (hot pink). Red tints will usually be considered pink as well.... but anything tipping too far towards the blue side of the spectrum will be considered to be lavender, lilac, or light violet.

>>pretty awesome deduction<< - Thanks

And thank you for such a detailed explanation - it does make sense. I can see how the specifics of it are going to be beyond primary level - but I can certainly see how thinking about colour and light in these ways will help me craft lessons that hopefully aren't comprised of 'lies to children'

I'm just playing about on your colour mixing site
Are the values for these all 225?


IN MIXING LIGHT:

Green + Blue = Cyan
Blue + Red = Magenta
Red + Green = Yellow
Red+ Green + Blue = White


IN MIXING PIGMENTS:

Cyan + Magenta = Blue
Magenta + Yellow = Red
Yellow + Cyan = Green
Cyan + Magenta + Yellow = Black

A computer will allow you to play with mixing actual light, such as in that mixer. I pulled it up with a quick google search, so there may be a better one out there.

In mixing Red, Green and Blue, 255 is the maximum on setting and 0 turns the color off.... or you can go anywhere in-between. In computer geekdom, someone made these arbitrary decisions long ago. 256 is a multiple of 8, which is what bits and bytes are based upon, so the settings 0-255 make for a total of 256 different computer screen possibilities.

By the way, you can make 256 x256 x 256 different colors this way.... which makes for 16,777,216 colors.

Allow me to bandy about some RGB computer numbers for demonstration purposes... I think that's what you're asking.

IN MIXING LIGHT:

Green + Blue = Cyan (Red 0, Green 255, Blue 255)
Blue + Red = Magenta (Green 0, Blue 255, Red 255)
Red + Green = Yellow (Blue 0, Red 255, Green 255)
Red+ Green + Blue = White (Red 255, Green 255, Blue 255)

(Note that the secondary colors of light are the primary colors of paint.)

IN MIXING PIGMENTS:

Here, we get into another way of noting color, due to physical properties of inks rather than screen phosphors. In offset printing, colors are applied in layers, composed of separated values of each ink. Each ink is denoted by a halftone value of 0% to 100%... 100% being the darkest and 0% being nothing. So....

Cyan + Magenta = Blue (!00% Cyan, !00% Magenta, 0% Yellow)
Magenta + Yellow = Red (100% Magenta, !00% Yellow, 0% Cyan)
Yellow + Cyan = Green (100% Yellow, 100% Cyan, 0% Magenta)
Cyan + Magenta + Yellow = Black (100% Cyan, 100% Magenta, 100% Yellow)

Again, Black ink is used to gain complete depth of darkness in most printing techniques.... since pigment colors are seldom perfect in their ability to absorb the unwanted light frequency completely.

Now, if you're mixing plain old paint...

IN MIXING PAINT:

Cyan + Magenta = Blue (Equal parts sky plue and hot pink)
Magenta + Yellow = Red (Equal parts hot pink and yellow)
Yellow + Cyan = Green (Equal parts yellow and sky blue)
Cyan + Magenta + Yellow = Black (good luck-- you'll probably end up with mud )

Truth is, paints seldom come in the purest values of primary color, so it's necessary to experiment in order to get a desired color. Adding white will produce a tint of a given color, while the addition of black will produce a deeper shade.

Example: White added to Cerulean Blue will make baby blue, while black added to the same color should produce navy blue.

In artists colors, it isn't possible to buy process magenta usually... Alizarin Crimson may be a good substitute. Cerulean Blue would be close to cyan and Cadmium Yellow Light would be a decent yellow to experiment with. However, paint is not designed to mix every color in the rainbow, so impurities will be present that tend to "muddy" the mix of certain hues. That's why this is called "color theory".... it should work, theoretically.

Oops.... that's 100% up there... not !00%. I got excited.

I can see where the teaching of Red, Blue and Yellow as primary colors started... because to a lay-person, magenta could easily be called red... but could be called cerise, crimson or berry red to another person. It's a matter of opinion when it comes to color names. Anyone looking at cyan would call it blue, because it is, generically speaking, an intense sky blue.

When people speak of color, the language is inexact... and no two people will agree on a descriptive term.

The problem we ran into in art class was that whenever we attempted to mix our true red paints with our true blue paints, we got a horrible purple color. It was tainted and muddy looking... but we never understood why. I understand why this happened now. The red paint contained a high amount of yellow, which served to mess up my violets. Yellow cancels out blue wavelengths and turns them to gray, which is what caused the disappointing "ugly" purple color.

I know, I know.... I go on forever. ;-P There is so much to teach about this subject!

no, no, no - this is fascinating - and explains a lot of past experiences mixing paints (particularly the 'brown effect' if we can call it that )

I'm (re)-grasping now why printing and photographs work the way they do - these are good examples to use for a classroom, so it may be necessary to explain the difference between paint and printing (ergo the difference in primary and secondary colours of light)

This all started out as a minor fantasy (if that is the correct term) of introducing light in science (I spent a vivid lesson one time about shadows, opacity, transparency etc - and explaining why we couldn't see the sun because it was behind a cloud - and that the temperature and light had changed because we were in the cloud's shadow.

I always imagined as a follow up to that lesson looking at how the rainbow is made (why clouds are white?, why are drink straws bent? etc) i.e. the the light from the sun can be split (and oh how I'd love to get the kids experimenting with glasses of water on a summer morning - but I'd equally love to use a prism to demonstrate Newton's discovery - I might even as an adjunct to that point out that spectroscopy can be used to study the Stars, planets and universe and tie light into the wider notion of cosmology.


...

like I said...fantasy. I'll be lucky if I'll get a class that can sit still long enough for me to mention rainbows.

also I get the 255 thing now. yes computer s - Tssh!

It also explains why when computer/TV companies boast "millions and Millions of colours" what they are quoting of course is the *potential* of any variable contained between the multiples of 256^3

You, my dear, are the most adept student I've ever had the privilege to teach about this subject. Awesome!

You may not have all of your color receptors intact in those eyeballs of yours, but your grasp of color theory is truly astonishing, Clive.

I'm at w*rk, so I may not be able to reply much more until this evening, but feel free to discuss and ask... I'll be happy to "essplain" in any way that I can. I don't claim to be an expert, because this subject of color is vast, but I love sharing what I know.

Well what can I say? Approaching the subject as I do, from one who is missing a channel, you might say I'm a bit obssessed with how colours functions (or indeed don't function) too!

Speaking of...just installed a new printer cartridge and yellow isn't being printed so everythign has this pinkish tinge to it.

The ways in which colors are defined in science are also fascinating! I do wonder, though... at the way color frequencies are measured in a linear way through science, and yet, the visual spectrum mixes in a circular way in practical applications. Why the divide?

I was told on another thread that magenta doesn't exist as a color of light, but it MUST! Apparently, magenta has no wavelength.... but this can't be! This person had to have been mistaken. I've meant to find an answer to the gap between the rainbow spectrum, which fades to ultra-violet and infra-red on either end, and the way in which colors blend on the computer and in printing, which is a closed, circular loop, rather than a linear depiction as in science.

Perhaps you could help me find that answer.

By the way, magenta is the missing color on the rainbow.... but it is absolutely critical to color reproduction in everything we view on-screen or in print. Why isn't it present on the rainbow? Indeed, (magenta) pink *is* the mystery element of the universe.




We need to go into some sort of color business together. I think you've helped me realize that color has always been a passion of mine as well. I've been thinking of going back to school to study "something", but haven' been able to decide on what that "something" should be. Perhaps I have an answer.

maybe we can try SEx?

A4108330

But what will Amy+ say?

Honestly, I've been completely overwhelmed by the genius geeks on those threads, but yes, they probably know the answer.

I've come to the conclusion long ago that my brain is in the sub-genius category.... therefore, I will be made into mincemeat on that forum.

It should, of course, be stated that anyone who feels an urge to try SEx should always carry a Community Of Normally Developing Ordinary Minds (badge)

I knew I liked you for a reason, you sick freak, you.