Feb 2012

RGB versus the Rainbow

Today’s installment will discuss two examples of REAL EYEBALL FUN that we are all familiar with… rainbows and color wheels.

 

 

Seeing a rainbow arc across the sky is no less awesome because you understand the science behind it. Seeing one in the spray of a garden hose or a hundred spread across the walls from the crystal in the window, it is clear that the same rainbow is being a universal signature of light. The red end is the long waves and the violet end is the short waves with all the other colors spread out in orderly fashion across the octave or so in-between. What a neat idea. Every color is a frequency or note just like a piano keyboard. How simple. This led to many ways to attach Christmas lights to speaker terminals.

Rainbows reveal how white light is made from a combination of colors so evenly distributed that one could not find a little spot anywhere that was more red than another little spot. Step out in the sun and hold out a piece of white paper. Notice how uniformly white the paper looks. Use a crystal or water glass to spread a small rainbow on the paper. Notice the purity and vividness of the bands of color and imagine if any one of them were to fill the page, how awesome that would look. Now, take the rainbow away. The funny part is, even without the refraction medium, all those colors are still there on the paper in the same proportions as indicated by the rainbow. Why aren’t you seeing them all at once? Where did this white stuff come from?

White light is something that happens in your brain. There is no such thing. We’re not seeing the crystal refract white light. We are seeing an abundance of red light being collected into the red area of the rainbow and so on with the other colors. We see the colors because refraction has caused a sufficient differentiation in photon landing patterns so as to be detectable by our EYEBALLS.

We know the light spectrum is really there. Light has a frequency that has a measurable wavelength. 470 nano-meters is a nice blue. Any frequency of light will be one of those bands in the rainbow. We can know what distant things are made of by seeing which frequencies of light are absorbed or reflected. The rainbow isn’t woo even though it sure looks like it might be. Rainbows and the light spectrum it reveals are Real Science that can be understood rationally. Hold that thought.

Aside from learning about the spectrum, we also learned about The Three Primary Colors. They were often depicted as a disc divided into thirds. We would see them in school and on PBS but they weren’t always the same. The Three Primary Colors are Red, Blue and Yellow or Green (like Shemp or Curly). This was the first of many color conundrums. Why, like that one scene on the airplane, couldn’t all four be part of the same wheel? Do you remember how logical it was when you saw it laid out in front of you in vividly colored Sorry pieces and electric glowly games?

National Geo had a page with a colored wheel that could be cut out and placed on a spinning record player. It would look white until it slowed enough to become seen as separate segments of color. There were color wheels that showed how two colors could become a third color. Color wheels became a craze. Many a bedroom wall was spotted with flying marker ink.

Back before there were CD players, their discs were painted and spun on spindles for color experiments. A disc that is colored half blue and half yellow will look green if it spins fast enough. Red and blue make purple in various shades depending on how the colors were proportioned on the wheel. Red and green make yellow. Really? I could get any kid to take an invite to come home after school and see red and green make yellow. I could take bets. I had pure green and red spotlight filters that together looked black but if I held it to a bright light with white paper held close, the little passing light showed yellow on the paper. Once the EYEBALLS believed it, the logic it gave to the color wheel was quite appealling. Up to a point, then it all falls apart.

So, why doesn’t red and green make blue, and blue and green make red? Red and Blue were like Moe and Larry. They were always there and could not be broken down or remade. Red and blue made purple and that was a whole other band of the rainbow. Or was it? Yellow and green just made yellow-green. Blue and green just made blue-green. Read the crayons. There is no red-green even in the 64 box. And what about the mysterious crayons that were in the box?

We’re you ever faced with this artistic dilema?... you want to draw a tree but your parents could only afford an eight pack of crayons. How do you make the tree trunk brown? If you think about it, there shouldn’t be any brown… or silver. Where is all the brown light then? Any brown in the rainbow? No. Yet there is brown all around. Apparently, light doesn’t start out brown, but only becomes brown after bouncing off of brown things. Have you ever seen silver light? Then how can things look silver?

Standing in the light bulb ailse at the “party lights” display, our current grasp of color is also on display. Party bulbs go by rainbow rules of color. Notice the orange bulb. It isn’t part red and part yellow even though the color wheel makes it that way. It’s just orange. Like the band in the rainbow. Now, grab a brown bulb and let’s go.

The horror of it was starting to become apparent. Color televisions don’t generate all the colors of the rainbow… just red, blue and green. Yet they show all the colors of the rainbow. Or, if in even amounts, the Three Primary Colors will show the Three Stooges in Black & White. If they are differentiated just right, they can create the glowing golden guy from CSI: Rock Music. The Primary Colors or, additive color, or “RGB” are all Real Science that can be understood rationally.

Have you ever tried to reconcile the three-color principle with the rainbow spectrum? It is worse than the particle-wave duality. The rainbow says that there is yellow light and it has a frequency. RGB says that yellow is what you get when mix a light red with a light green. RGB suggests that, like white, yellow is something that happens in your brain. The spectrum says that yellow is really there in the sky.

These and other dilemmas became clues to solving the mystery of silver, brown and the RGB-spectrum duality.

Other clues can be found in the popular video test signal known as “the color bars”. Three of them are an illusion.

That’s where we will pick up the trail… next time.

One more clue. Look at the color wheel below for a whole five seconds then look at a blank wall. Negative colors. Just like color film negatives. Now I’ve given away the store.

 

 

 

We use our EYEBALLS to look at all sorts of things but I think it’s time they looked at each other. For some, that may be as easy as looking cross-eyed into a closely held mirror. The rest of us can keep staring ahead. Chances are, you’re looking at a vid screen right now.

We learn all kinds of stuff from our video screens everyday. Today, we will learn about vid screens and what they can tell us about our EYEBALLS, which, for convience, you can leave right where they are.

Most of us flip right past The Color Bars when surfing the cable. That is likely because, like EWTN, we have no idea what we are looking at. The truth is, those colored bars have more to say about reality than most channels. The truth isn’t pretty but fortunately, the colors are. A simple color bar pattern is shown below. 

 

 

 

 

Of the six colored bands, three of them are the same as the color wheel above- red, blue and Shemp…  I mean, green. The so-called primary colors. If you did the staring trick (count to five while staring at the wheel, count to five while staring at blank space, then the negative image appears) then you have already seen the other color bands- magenta, cyan and Curly… I mean yellow. Since a TV makes white from a red, a blue and a green screen all at full tilt, those three other “secondary” colors can be made by subtracting one of the primary colors from this so-called “white”. Take the red away and the screen is cyan. Take the blue away and screen is yellow. Take the green away and the screen is magenta. Any modern LCD TV or monitor has a menu with RGB levels and you can try this yourself. Just remember where they were set.

So now, if you were really determined to have a sensible conceptual color wheel in your head, you would think you had it made. Now the wheel has six sensible segments- three real colors and three phantoms or negatives or anti-colors. They have a nice logical reversible symmetry. Once you get the idea, you can perceive it within the Chunk Limit. That means it’s a comfortable, un-narrated thought. It’s even vaguely rainbow like. Imagine a tubular rainbow. Our brains can do that, so maybe we’re on to something.

The next time you print out an article on deforestation, notice how printing supports the color wheel scheme. There’s no rainbow in the ink cartridge. The computer’s printer makes color via subtraction from the white of the paper or, “CMYK” (K for black). Notice that the color ink cartridge contains cyan, magenta and yellow. Equal amounts of magenta and yellow with no cyan make red. Equal amounts cyan and yellow with no magenta makes green. Leave out the yellow and you get blue. Black is added to darken the colors.

Back to the bars… notice that the left side has lighter colors and the right side has darker colors. Each band has a slightly darker “grey level” than the band to its left. The truth is, that’s where the real truth is as far as our EYEBALLS are concerned. Our EYEBALLS started out as simple bean-counters that tracked the bulk weight of photons that passed through its dual optical sphincters. We call it “brightness”. Our brains have used the bean-counts to re-map the world in front of us as a mental sensation. Prof. Darwin (used here as a figurehead for a body of opinion) would remind us that our ancestors did this to be successful and not clever. Once success was achieved and evolutionary pressure was relieved, further cleverness was not pursued. Our EYEBALLS used brightness to make us happy, which is just what your vid screen is doing.

 

 

If you turn the color level all the way down, the pattern becomes seven bands of grey that scale light to dark. They should appear to be even increments of darkening from left to right. Your TV’s Gamma control will adjust how light or dark the middle bars are by stretching the grey-scale toward light or dark. Contrast will control the range or distance between the darkest and lightest the picture can get. Brightness just collectively changes the whole light level up or down. These are all things our EYEBALLS can do. It’s all about mapping light intensity. In tech-talk, it is called the TV Luminance Signal. If you’re watching a black & white movie, it is all you need.

If you sat too close to the TV screen, you likely noticed how the picture is lots of rows of dots of light. Each dot has one light level. Together, if you move back enough, they form a picture to your EYEBALLS. But really it’s a big map of light levels. The reason it works is that inside your EYEBALLS are lots of rows of little light receptors making a big map of light levels. All the picture adjustments listed above are done right there in the EYEBALL. By the time the “picture” is sent down the chute, it is already much happier than the raw photon stew it was drawn from.

This should explain our tendency to see “optical illusions”. Those are brightness maps that, while making us happy, do not stand up to a narrated, post-cinema examination and must re-explained in order to make us intellectually happy. It may be truthier to think of optical illusions as “sight” and that these illusions come in two forms- successful and unsuccessful. There is no reason to see “color” any differently.

The truth is that the color wheel is our EYEBALLS’ way of making us happy by making up colors that they can’t possibly know are there. Not for sure. The Three Primary Colors are three narrow bands of the rainbow that our EYEBALLS have selected as the most useful in bringing us optical happiness. Why three? Why not five? There is no way to fit five fields of color-tuned light-mapping sensors into our EYEBALLS without limiting their ability to see luminance detail (which was still vital to happiness) or by slowing the rate at which maps could be created.

So, while the rest of the rainbow of colors are really there, our EYEBALLS are only pretending to see them. Based on a large body of evidence connecting rainbows to happiness, it is natural that our EYEBALLS should consider the job done.

Vid screens and color bars are made to create the Color Wheel o’ FUN specifically for primates with EYEBALLS like our own. Other species developed different color wheels based on two or even four bands of “real” color. Our vid screens may look very different to them. They may see better, happier rainbows or none at all. That’s a sad thought to a primate.

Next time: Weird Crayons Explained.

 

Later that day... 

 

My family had a very slow-starting black and white TV that needed to be turned on well before the show began. I saw the first run of Star Trek in B & W. I was keen to know what color all the things were… like those shirts they didn’t have to tuck in. After seeing pictures in the TV Guide and remembering who was red or blue or gold, I could recognize the grey scale and always know which one anyone was wearing on the show. My brain would sort of put them there afterward and I could remember the show in color.

 

 

It was surprising to learn that Star Trek was shot with black and white film. Hordes of diehard Trekkies painstakingly hand-painted each frame before it was aired. Actually, like most color TV shows of that era, it was shot with black and white film. Color film was incredibly expensive and could not be wasted on bad takes. So they made these crazy cameras that split the light from the lens to three film gates and shot three reels of cheap B & W film simultaneously. The gates had color filters so each film saw only red, blue or green. That makes each film slightly different in just how grey things are compared to the other two.

 

 

After the show is cut and timed, and all three “RGB” films are edited exactly the same way, a big crazy machine plays all three simultaneously through red, blue and green filters and combines them into a single image that is transferred to the hi-priced color film stock. It makes sense since the TV only shows red, blue and green anyway. Or, like mine, it shows no color at all and presents the average of the three grey scales put together. The recent re-issue of the old series was rebuilt from its three RGB films with all the FX updated with CGI by aging hordes of diehard Trekkies. “Doomsday Machine” and “Galileo 7” (!) will blow your occipital lobe.

Any lingering sense that color is like something that can come out of a faucet should be gone. Any so-called color we perceive other than red, blue or green is made up in our brains. So why do the colors in our brain match the colors of the rainbow? Because we see an RGB rainbow in our brains and not in the sky. All that is actually out there are lots of wiggly photons hurling at you that have been segregated into little neighborhoods on your retina by their particular kind of wiggly-ness. In real estate, this is called “red-lining”.

Like the TV cameras, we have three “fields” of light-level mapping receptors in our EYEBALLS each tuned to a particular range of photon wiggliness or wavelength. All that refers to is how much closer to your EYEBALL the photon gets with each complete wiggle. Photons that wiggle fast and hence cover less ground per wiggle have a shorter wavelength. One of our EYEBALL receptor fields sees our favorite short wavelength photons- the ones that travel 450 nano-meters per wiggle- and makes a light level map of those with a gradual blindness to wiggles much faster of slower. It’s a grey scale that favors high-frequency light. Another mapping field favors low frequency or long wavelength light that borders on the sort of energy wavelengths that other parts of our body are sensitive to as heat. Like the “R” film of Star Trek, it is just a grey-scale or brightness map that doesn’t really have any “R” in it.

The third field in our EYEBALLS isn’t as simple to explain. It sees a narrow mid-band of wavelengths and is the most sensitive to light intensity (photon bulk) of the three. In dimly lit spaces, it is still making useful grey-scales while the other two have bottomed out and gone dark.

Warning: The rest of this post cannot be fact-checked with wikipedia.

There is a controversial new theory that has been ignored by everyone until right now. It’s called the Third Stooge Theory and it tries to explain why our color perception is variable and subject to so many visual influences. It is possible that the middle range “green field” of our EYEBALLS actually offers a selection of wavelengths to tune to depending on the sort of light they are experiencing. So this third color of the Three Primaries is a floater that can see slightly different grey scales depending on how it is tuned. At any moment of sight the third band must be fully Shemp or Curly and can never be both. That doesn’t mean that there couldn’t be other mid-band tunings as well that could give us Red and Blue plus Shemp or Curly or Joe or even Curly Joe Derita. These would all be particular bands of green and yellow-green but another possibility is that our green band is continuously varible over some modest range. As if the third stooge could be any one of an almost infinite number of intermidiate states between being fully Shemp or fully Curly.

 

 

So, is there color in our EYEBALLS? No. Three color-biased grey scales are produced and their levels are adjusted. Distribution is complicated and handled in the optical stem. Simple functions like detecting movement or spotting a certain color (seeing an area that differentiates the three grey scales just so) make instant alert signals to our sub-cinema perception. Like the instant impulse to quickly move our EYEBALL SOCKET MUSCLES and aim our EYEBALLS in the direction of a sudden movement. Sub-cinema signals keep our EYEBALLS aligned and stereoscopic depth info is sent straight to muscle control for good eye-hand coordination. At the same time, whole visual fields are being organized for the cinema view at a slower rate. That’s when color arrives. Grey scale differentiation becomes a sensation of color and is incorporated into each EYEBALL’S visual field that then combine to make the cinema view. …in our brain, and not in our EYEBALLS. By the time the cinema view sensation arises, our EYEBALLS are already gathering the next frame.

When viewing one of the earth’s many awesome scenic landscapes, it is hard not to wonder how Nature could not know that it looks like that. No, it is only the colors that Nature determined were the minimum necessary to make primates happy. Why happy? For the same reason that sex makes us happy… so we will make more EYEBALLS.

 

 

In this final episode of RGB vs The Rainbow, the magic will be revealed… the perps will be apprehended… and the New Rainbow will be introduced to all.

Like the particle/wave duality, our traditional concept of color has developed a conceptual quagmire. The rainbow world of color that is actually out there and gives us Qualia Tingles conflicts with the modern RGB color of TV and film. RGB admits it’s fooling you. Could the rainbow be fooling us too? Somebody’s lying. As usual, it’s us.

In the battle between the world of RGB color and the rainbow spectrum there can be only one winner. And that’s you, for learning how color works in YOUR EYEBALLS.

Here’s a recap of the trail so far…

Light is composed of wiggling photon trails that travel really fast. How much distance they travel during one wiggle is called wavelength, and how many wiggles per second is called frequency. Either is describing the rate of the wiggling of light waves/particles/whatzits. Light has lots of wiggle rates but they all fall into a range of frequencies called a spectrum. Outside of that spectrum, wiggling energy takes other forms… heat below and xrays above. But inbetween, it’s light. 

 

 

 

That’s almost a lie already. Light is the form of energy radiation that OUR EYEBALLS can sense. If there were NO EYEBALLS, the world would not be illuminated. Nor would it be dark. It would be unseen. Photons would keep bouncing off of things but would never become sight. This discovery led to the first fatality of the conflict. Color itself.

Sadly, there is no color out there. It can’t pour out of buckets. Leaves aren’t green, they simply absorb and reflect a particular combination of photon frequencies. Light is full of different frequencies that reflect, refract and converge in a variety of complicated ways. All that changes when we put OUR EYEBALLS in their path. That gives us a chance to see a small portion of the surrounding light… just the trails that are coming straight at us.

So, we could blame OUR EYEBALLS for color, but they aren’t guilty. Not that we didn’t catch them at something. Turns out, they have been hoisting the Illusion of White on us since the very beginning. White is what happens when all the arriving light frequencies are sort of even-steven. Except that they are not completely even and equal… it is just a threshold where OUR EYEBALLS can no longer discern any unevenness.

So many illusions destroyed already, and no resolution to the conflict in sight. What about hearing?

If you have a basic home theater set up somewhere, it has three speakers across your front perspective- left, center and right. If there were three microphones in a row outside the house and each was connected to one speaker, a passing car would seem to pass across the speakers inside. There would be a mid-point of the car’s passing that would be loudest in the center speaker and much fainter in the left and right. There would also be a point where the sound comes medium loud through the both the left and center speakers equally. If the speakers are well matched, the sound will convincingly seem to be coming from the mid-point between the left and center speaker and not perceivably from both of them.

Technically, this is because of how sound waves sum or combine in the air space of your room, but that fact is not handy right now. I have all the metaphor we need. Next, substitute left, center and right with red, green and blue… and the passing car with the rainbow spectrum- red on the left and violet on the right.

Green goes straight into the green microphone and comes straight out of the green speaker. Likewise with red and blue. Light in the yellow range is picked up by the red and green microphones less loudly but about equally. Inside, that makes yellow appear to be coming from the space between the red and green speaker. Cyan comes between the green and blue speaker. Magenta appears when red and blue appear without any green inbetween. Orange is three-quarters or so to the left.

That would seem to satisfactorily explain how the whole rainbow of colors manages to get in through just three portals. But color has not entered into it yet. The trail has yet to catch up with color. All the red, green and blue microphones are hearing is the loudness of their own exclusive stretch of the spectrum. Likewise, our red, green and blue receptors detect only the brightness of their exclusive frequency window. There is no need for color yet.

Film and video saves lots of money by duplicating the process. Even Gone With the Wind was photographed entirely with black and white film that was only sensitive to brightness and blind to frequency. One camera records on three reels of film simultaneously. A carefully chosen color filter is placed ahead of each film gate so each film sees an exclusive range of frequencies. The result looks like this…

Can you identify which is representing red, green and blue? Bonus points if you name the episode. 

 

 

 

 

After the three black and white films have been cut up and the outtakes discarded, they are simultaneously shined through the same color filters and combined onto one expensive reel of color sensitive film. That’s what “TechniColor” is. It’s technically color. Funny story there… you remember those digitally remastered GWTW videos we all bought a few years ago? More lies. All those commentaries about the cinematography are turning red. Turns out, GWTW hasn’t been seen with the correct color filters since its initial release. Sepia tonality indeed… turns out, it’s as stark in color as 2001 (the digitally remastered version, of course). Time to yuk it up and buy the new version. Or hold out for the 3D interactive version coming soon.

Less funny is that these color filters were identified with numbers. Like a code that encodes colors. Such a code was invented about 80 years ago. It’s called the CIE Color Space Chromaticity Diagram and it was a bold and honest step down the path that led to the true whereabouts of color. It involved building a better rainbow. Here it is…

 

 

Actually, there are no unicorns. I only wanted to soften the impact.

It looks chaotic at first glance but there is a simple order to it once explained. If you look closely at the top edge (the rounded A shape) you will spot the old rainbow now stretched out sideways across that whole arc. Red and blue are near the bottom on opposite sides with green across the top with the familiar smear of rainbow shades between them. It’s sort of white-ish in the middle but there’s a blurry moat of shades around the center. It’s best and easiest to understand trick is as a color pie chart for drawing pencil lines through. Add some lines, and the blurry moat part makes sense.

Take any two points of that outer arc (as in, pick two places along the rainbow spectrum at the outer edge), and draw a pencil line that connects them. The mid point of the pencil line lands on the shade we would “see” if those two frequencies of light were detected by our RGB sensors. It works with multiple points but two reveals the trick. 

 

 

Next in detail are its three corners. Rainbows didn’t have corners before. This one captures the rainbow/RGB duality in its odd shape. Paralleling the rainbow spectrum along the edge is a number scale. These numbers are the actual wavelengths of light in nano-meters, which are real tiny. Three dramatic slash marks rip through the outer edge to proclaim the exact positions of the microphone/light receptors from the previous metaphor. On the lower left, Blue reception is centered on the wavelength of 470 nanometers. It grows gradually deaf to wavelengths above and below that value as do the other two reception points. Red is around 650, Green is around 560.

If you can pencil line your way to the center point of the three slash marks, you will find a human’s perfect idea of white.

The distance from each corner to center represents the light sensitivity of that particular receptor. Our Green sensor is the most sensitive hence it takes more Green signal to combine into a happy white… hence its corner bulges out much farther than the less sensitive and tucked in red and blue receptor/corners.

This is actually a three-dimensional chart surrounded by distracting x and y scales. The Green end tilts way up on the Z axis. This is to establish exact coordinates within the new rainbow. That way, very precise shades can expressed as numerical coordinates… including the colors of the correct filters for GWTW. There is one more simple feature worth pointing out here. There is more than one way to achieve that perfect white in the center and it’s where the rainbow/RGB duality ends. 

 

 

One way is to put all the wavelengths across the whole spectrum into our receptors at once at brightness levels proportional to the distance to the center of the chart. Plain incandescent light bulbs do exactly that.

Actually, bulbs decided the chart, and we just presume it corresponds to our receptor sensitivities because the consensus is that it makes the happiest white and makes solo colors pop about equally. Another way to make white is to input just those three exact wavelengths of the receptors alone at those indicate brightness levels. We experience the same happy white even with all the rest of the rainbow spectrum silenced.

This is easily demonstrated with a spinning color wheel of red, blue and green. When it spins fast enough, it turns white.

At this point in the tale, we have white completely surrounded. It is, in the end, a fraud. It is, simply put, the limit of the wavelength discriminating ability of OUR EYEBALLS. It is a whitewash that blinds us to the colors beyond our limited resolution.

But that’s more lies. It never stops on this trail. They’re not colors. They’re frequencies or wavelengths. Color is the sensation of seeing them.

It is like saying, “The taste of chicken is actually in the chicken.” Or, “All the people in the phonebook are actually in the phonebook.”

We wonder if we all see the same red. I think we do. We feel the same cold. We taste the same chicken. We smell the same rose. Like all those reactions, Red is a creation of human biology and is probably the same for us all.

And that brings us to the last victim of this crime spree and the most recent. Still warm, but fading fast. So gradual… we almost didn’t notice it fading away. Maybe it isn’t too late to save Red. We’ve identified the perp. Here’s what happened…

If you look again at the new rainbow, you can see how a line that starts right on the blue mark (470), and aims itself straight through the white middle, will come out the other side in the yellow orange range. Aha! A simple way to whiteness! Exhibit A: The LED. It’s its MO. 

 

 

This paragraph is updated because I cheated a bit for brevity. A recent noble prize recipient gave us the blue plasma LED that makes the new lights we are all getting to know. Previously, the diode junction would glow at a frequency related to the material used. Usually, red or greenish. This made a fine panel indicator but not a desk lamp. Once this breakthrough of blue was achieved, white LED's became practical. A little bed of red, yellow and green phosphor is added inside the casing which, when excited by the energy from the diode, emits a fairly broad range of yellow light because, without blue, red and green make more yellow. With just the right balance, a sort of white will result. Not that it is white “out there”, it’s just a way to trigger the sensation of white in our brains.

There was a way to make work at least on paper and that became the way we measure the color of an LED. It’s the Color Rendition Index or CRI. It’s simple… ish.

Recall the blue to yellow line that crosses the white zone… actually, it’s a 3D arc in the 3D chart… if we pick ten or so spots on that line near the white center, we can measure that light from the LED and see how close it comes to the level of that light from an ordinary bulb. Then we can average the ten spots together and give a number to how “white” the light is. If all ten spots match the bulb 100%, that’s a CRI rating of 100. In practice, LED’s tend to measure from 50% to 80% of the color of a bulb. That percentage is the CRI number. But that too is a lie. It’s just blue and yellow.

Why bother with reality when you can cut straight to the illusion? That’s all it is anyway. We pay a price for that logic, and the price is seeing red. Green was spared much ill effect because that receptor range is very broad and sensitive. And it lies between blue and yellow in the spectrum and we’ve all seen blue and yellow make green. Red sits beyond yellow and far from blue. Its range is just broad enough to be tickled a bit by the phosphor light. Reds look dull in LED light. There, but wimpy.

 

Hopefully, continued progress in the technology will discover a cheap way to put Red back into White. Until it’s cheap, the bean-counters will never go for it. And LED CEO’s are in no hurry either. When asked if there was a particular color they just didn’t care for, the reply was…

“Frankly, scarlet. I don’t give a damn.” 

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