Slashdot Mirror
RGBS: Color Spaces For The New Millenium
Snowfox writes: "Crosley Bendix, Director Of Stylistic Premonitions, U.M.N., has this excellent article explaining Squant, the fourth primary color. He managed to get his hands on a new Apple Quicktake 1500sq, in advance of the US release, to snap some photos. You can view them with the plugins available on the site. -- Sorry, no Linux plugins. :( -- Seeing a new color jumping off your screen is a real head trip though. Just try and imagine a color you may well have never seen before." While it's true that no Linux plugins exist yet, a GIMP plug-in can't be far away. Considering Squant's olfactory characteristics, that might not be the greatest idea, though.
My friend frantically calls me up and says to me "There's a big problem!!" I say to him "What?" he goes "I can't install the Squant plugin! I can't see squant! " so I say to him "uh... that's a joke. you know that right? " He replies that I'm an idiot, and after about a minute realizes he's wrong. Looks like someone reads /. too religiously.
I was toying with the idea of writing up these aliens in some sort of roleplaying game.
Now, the interesting questions that arise are:
Don't label something "offtopic" unless you know the topic well enough to tell what's on topic.
#include stdio.h
#include unistd.h
int main(int argc, char**argv)
{
printf("RGBS plugin v2.00 (C) 2001 Fjear-Nation.net\n");
printf("This product includes software developed by the University of California, Berkeley, and its contributors.\n");
printf("This product includes characters standardized by ANSI, ISO and their contributors.\n");
printf("This product includes words in a language developed by the People of England.\n");
sleep(2); fprintf(stderr,"Unable to initialize RGBS plugin, error 566: PEBCAK situation.\n");
return 1;
}
This is a genuinely funny hoax, but you should know that it is as almost as old as Slashdot itself. I first came across it in 1998, and I notice that the page hasn't been updated since October of that year.
On the general topic of April Fools stories, I suggest in future years you take a cue from the mainstream media, and just embed one carefully chosen hoax amongst a slew of actual news.
Monochrome monitors and black and white televisons have only one electron gun and the phosphor at the front of the tube that gives off light when struck by those speeding electrons is all of the same type.
A color television or color monitor has three electron guns and three different phosphors are used, one for red, one for green, and one for blue.
In most CRTs the guns are arranged triangularly and the little dots of red, green, and blue phosphor are also arranged on the screen in triangles. Some CRTs stack the guns and the phosphor triads vertically.
If you were implying that the person to whom you were replying was using a monochrome monitor, then never mind, except that creating a system that uses 3 or more different colors of phosphor but only one electron gun to light them up would be hideously difficult and horribly expensive.
I see even classic Slashdot is now pretty much unusable on dial up anymore.
Interference between two frequncies creates a third and fourth frequency, the sum and the difference. This is what allows radio and television tuners to use a variable local oscillator to create a signal at the fixed frequency for which the intermediate frequency amplifier chain is tuned. To learn more, look up hetrodyning.
I see even classic Slashdot is now pretty much unusable on dial up anymore.
The best part is when you click on customer service and go to the NewHew SquantView Troubleshooting Guide. Especially if you're a BOFH fan.
I see even classic Slashdot is now pretty much unusable on dial up anymore.
RGB is indeed the primary colours for mixing light, but the colours for pigment are:
Cyan
Yellow
Magenta
The reason RYB is often quoted is that Cyan and Magenta are not colours commonly used, and they look a lot like blue and red.
Ok, first off, 'light' or visible light, is the portion of the electromagnetic spectrum with wavelengths from about 4*10^-7 m (violet) to 7*10^-7 m (red). If you 'mix' two sources of light, each of their own frequency, they to not become a third frequency.
The reason light 'mixes' is based entirely on our biological response to it. It just so happens that when we see red and green light at the same time, our retina responds about the same way as it would to pure yellow light.
Now, we consider red, green, and blue to be the primary colors of light because we can fool ourselves into seeing most other colors with combinations of them. Again, this is a result of our biology.
In fact, there are colors in the visible spectrum that we can see that _cannot_ be simulated using a combination of red, green, and blue. Likewise, there are colors that can be produced with red, green, and blue, that cannot be reproduced with the absorbtion of cyan, yellow, and magenta from white light. Hence the development of Hexechrome, a 6 primary ink system from Pantone, that can better approximate red, green, blue.
So it's perfectly reasonable that given a forth color of light we could expand the range of simulated colors to better approximate the entire visual spectrum. In fact, there are color systems, LAB (luminence, a, and b) and probably others, that allow us to store more color information in a file than our RGB monitors can reproduce. Anyhow, I hope this straigtened out a few people, although I hope I didn't confuse anybody into thinking this article was legit. It ain't.
I think I agree with you about the headroom aspect - I saw a demo with a landscape generator. They used logrithmic brightness because it let them have nice bright mountains and still have the sun appear brighter. (I say "I think" because it's not quite clear what your point was.)
But, how does wanting 16bpcc (color channel) require a monitor capable of 256 times more light output? The problem is that if you display 256 equal width bars of a color across the screen they appear as distinct bars. That's with 8bpcc. So wouldn't it be nice if you could draw 65536 (or rather, as many as you had lines of resolution) different shades of a single color across the screen to avoid the banding?
And yes, FP pixels would be great. It'd remove the inaccuracy we get simply from repeated truncation of the values, after every blending effect.
Actually, I want a much larger numeric range to cover the color range currently represented by 0-256. I don't want the top end to be much brighter, or anything. Just a smaller difference between levels.
It's barely obvious where the color bars meet if you do a 256-step gradiant from black to full red, for example. I think with each of those steps being represented by another 256 steps, it's be impossible to see the difference.
And going to a higher resolution DOES solve the aliasing problem. Take a 2048x1536 picture, shrink it to 256x192. Display both full-screen. See the jaggies in the smaller one? Those diagonal lines were just as rough at high resolution, but the pixels were smaller and less obvious. Once the size of a pixel drops below our visible threshold we won't see that anymore.
Of course, perfect knife-edge rocks against a blood-red sky happen rarely in real life, so Q3 won't appear 'correct' but the jaggies will be gone.
Dithering isn't the best solution for approximating a color, it's merely the best available.
>I think part of the problem is that we're coming from different domains here. My company writes
>software for people putting images onto film. (Visual effects, mostly.) Therefore we need to
>handle the huge dynamic range of film. People playing Quake don't need that.
Quite right. I want something that makes my graphics look nicer. Dithering is a hack we shouldn't have to use, so I want more detail where it would do me good.
Now, I wouldn't complain if it was decided to stop at 12bpcc (4096 levels) and make the rest headroom, for the benefit that would have for people working with film. (16bpcc is a bit excessive).
And yes, in this quest for less banding, I'd love floating point rendering so that fog effects didn't look so ugly.
As for the aliasing, I was talking only of a stairstep effect on a diagonal line. I agree that there are other aliasing problems, like oversampling, or moire effects from rendering fine lines. Those do need more sophisticated handling than simply more resolution.
As for the "only where it matters"... it would be a nice step if we made better decisions about that, when to drop the quality on a model so as to not make it a visible difference. The problem that I see is that when a model is dropped in complexity the textures tend to shimmy. We need a better way of locking textures, maybe to the center of a polygon instead of the edge.
As for Moore's law, yes, people seem to expect us to be done soon. What's really happening is that we're discovering tasks that couldn't even be considered until recently, faster than we're 'finishing' old ones. (For reference, Doom tops out of 35fps, and I don't know how to change that, Quake 1 gets 300+ fps, Q2 gets 220+, Q3 gets 110+, and Q3TA (larger, more complex maps) gets 75+.) And it has a long way to go before it looks real.
How can this plugin add a color-gun to my CRT monitor? Adding hardware with software sounds little too 1337 for me.
I don't get it! I downloaded the plug-in, tryed it in IE and Netscape, reinstalled it, even tried it on a friend's Mac a few times. But as hard as I try, I still can't see Squant!
"The fact is, there is no language to explain colours to someone who can not see them. It just can't be done."
;)
As a colorblind person, I can confirm this fact 100%. I don't know how many people have attempted to describe to me what color my shirt is.
> ...did you know there are some tribal cultures
> that only have words for 2 colors? And there
> are some cultures that distingiush between over
> 200?
I'm not sure if the employees of "Crayola" constitute a "culture".
Unless you're working with film, you don't need it. Eight bits per channel is adequate, and will remain so until we have monitors that can deliver 256 times the amount of light that current ones can.
I've posted two comments on this topic previously. Go have a read.
Having said that, one place where we really need more precision is in the intermediate buffers of OpenGL (e.g. the accumulation buffer). But what you want there is floating point pixels.
sub f{($f)=@_;print"$f(q{$f});";}f(q{sub f{($f)=@_;print"$f(q{$f});";}f});
First off, I said that 16bpcc would only be useful if you had a monitor capable of more light output. I stand by that. (Note: 256 is too much, of course. :-) What you really want is 0-4095 be equivalent to the current 0-255, and the rest as headroom.)
As for 256 equal width bars appearing as distinct bars: of course they will. The human eye always looks for discontinuities, causing the Mach banding effect. What you have here is an aliasing problem. Just like going to a higher resolution doesn't solve spatial aliasing problems (I can see the jaggies on the sides of polygons when I play Quake at 1600x1200, which is better than HDTV), going to a higher colour resolution doesn't solve colour quantisation aliasing problems either. You really need something like stochastic sampling to hide the aliasing behind noise. In this case, you need dithering.
sub f{($f)=@_;print"$f(q{$f});";}f(q{sub f{($f)=@_;print"$f(q{$f});";}f});
I think part of the problem is that we're coming from different domains here. My company writes software for people putting images onto film. (Visual effects, mostly.) Therefore we need to handle the huge dynamic range of film. People playing Quake don't need that.
If the scene that the 2048x1536 image was meant to represent has even higher frequencies in it and that image was not properly filtered, you will see aliasing problems. Especially if this is an animation frame, or if there are fine objects such as hair or fur (although shrinking it properly, using a sinc or Catmull-Rom reconstruction filter will help this a lot). This is particularly noticable in the early films which used CGI (I'm thinking in particular of The Last Starfighter). They rendered larger and then shrunk the frame down for printing onto the film plates. For the most part it looks okay, but you can often see "sparkling" around the edges or on complex textures, because regular sampling never removes aliasing, it just moves it up a few octaves. Modern renderers don't do that. They use stochastic sampling instead, which also doesn't get rid of aliasing, but it does convert it to random noise, which is less visually objectionable than aliasing.
[Aside: I noticed the "sparklies" in the opening battle scene of Lost in Space when I saw it in the theatre, and you really notice it in cheap TV effects, like the first series of Babylon 5 or pretty much all of SeaQuest DSV.]
Worse than aliasing, though, that is the fact that it simply wastes computing resources. If your shading is properly filtered (for OpenGL that would include properly filtered mipmapped textures; for offline rendering that would include analytic integration), you don't need the higher sampling rates everywhere, only where it matters. The computrons that you expend on rendering at a higher resolution could be spent on more complex models, which would pay off better for realism. By comparison, Pixar reports that faithfully modelling a typical room in a house requires about 2Gb of compressed model data. For a game, you wouldn't need quite that much, of course.
One thing that's misunderstood about Moore's Law when it comes to computer graphics is that peoples' expectations increase as computing power increases. Nowadays, we can do Doom at 85 frames per second, but people don't want Doom, they want Quake 3. Which means that to keep up with both you need to work smarter rather than harder.
sub f{($f)=@_;print"$f(q{$f});";}f(q{sub f{($f)=@_;print"$f(q{$f});";}f});
At the moment, scietists don't know what makes up at least 88% of the universe. This claim has been verified by scientists' observing the effects of gravity on objects in the night sky. To account for odd galatic rotational curves and inexpicable escape velocities, cosmologists coined a term - "dark matter."
Recently, a friend of mine was fortunate enough to beta-test an alpha-version of the QuickTake 1500sq. I suggested that he try snapping a shot of the sky using the QuickTake and a new NikkorSquant telephoto lens. Our results were astounding. Here's a picture of the night sky that I made with my Nikkon Coolpix; and for comparison, here is one that my friend took with the 1500sq.
If you have a new squant-enabled monitor, it is obvious that a great deal of the matter in the universe is actually squant-colored.
"Why haven't other astronomers discovered this truth?" you may ask. Well, most astronomers are near-sighted and wear glasses. Unfortunately, at present, all glasses are manufactured with materials that are opaque to squant and do not transmit the new hue properly. Also, all telescopes currently in use do not have squant-compliant optics; as a result, squant cannot be detected on any equipment of this sort. Squant optics are so expensive and so volatile that most scientists will not be enchanted with the idea of having to retrofit Keck with squant optics.
In the 1930s, Zwicky and Smith, two fellows who were observing the Coma cluster and Virgo cluster of galaxies' velocities, were criticized for their work. They were attempting to estimate the mass of the clusters given escape velocity. However, these fellows were critized for a phenomenon known as 'contamination.'
However, I hypothesize that this 'contamination' was actually the presence of large varieties of Squant-colored mass (SCM) inside of the Virgo cluster. This 'contamination' was actually caused by spectral absorption of squant-colored emissions by other matter present in the cluster. This matter was excited by the squant-colored radiant energy and re-emitted light at lower wavelengths - much more like the better-known phenomina of "phosphorescence." Perhaps "squantphorescence" would be a more appropriate term for this sort of visual contamination.
Learn from your parents' mistakes: use birth control.
Looking for Madam Tetrachromat
Actaully, if you look at the wavelength of Red, Green, and Blue you will notice something interesting.
Red is a greater distance higher than green than green is to blue, meaning that a wavelength between Green and Red would in fact be an altogether fourth colour, which is exactly what the Tetrachromat would see.
How their brains interpret this data however is totally beyond explaination to those of us who have "normal" three colour vision.
You can't say it's like another shade of red, because saying that is like saying green is another shade of blue. It is not.
The fact is, there is no language to explain colours to someone who can not see them. It just can't be done.
"Everything you know is wrong. (And stupid.)"
"Everything you know is wrong. (And stupid.)"
Moderation Totals: Wrong=2, Stupid=3, Total=5.
#2. Photons tend NOT to interact, and pass right by each other.
#3. The human eye has a range of color perception, called a color space. This range includes colors that can NOT be accurately reproduced by CRT or LCD displays. This has been known since before the design of color TV.
#4. There is strong evidence that some people can actually percieve a fourth color, in the blue-green range, that most people can't. Slashdot had a story about this about 2 months ago. These people would be able to distinguish between to sets of carefully balanced lights which were composed from different colors of red, green, and blue LEDS, but appear identical to everyone without this extra sense.
#5. Slashdot needs another axis for rating, funny, correctness, etc.
--Mike--
Make you think don't it...
The message on the other side of this sig is false.
Personally, I'd hope that as our electronics D/A converters get more accurate, we'd shift to more colorspace resolution. 48bpp (16bppR, 16bppG, 16bppB) is the next logical step, along with a 16bpp alpha channel, to give a natural 64bpp step.
While it's true that the human eye's sensitivity is right around 200 levels of gray, unable to see finer distinctions, a human can very easily see the mach banding in ramps of other more subtle hues in the 24bpp color resolution space.
I've heard Hollywood typically uses 48bpp for the special effects graphics, and there's some 16bpc (bit per channel) features in GIMP and Photoshop, but I don't know much more about how we're advancing for hardware support there. I just want better colors!
[
Read the EFF's Fair Use FAQ
Have a look at this page from Adobe's online guide to colour theory. It's very informative and should help clear things up.
Actually, no, the primary colours of pigment are Cyan, Magenta, and Yellow. The whole RYB thing is a myth propagated by artists and ignorant high school art teachers over the years, which has nothing to do with the actual physical characteristics of colour and how our eyes perceive it. I had this sort of thing ranted at me for a semester in Colour Theory class, and it's actually quite interesting. This my help clear some things up.
this is for the mutant tetrachromats.
-no broken link
Man, you haven't lived until you've grown octagonal rods in your eyes and seen the eighth color, octarine, the color of magic.
Of course I can't describe it to you, but it's sort of a purplish-green....
-J
Karma: T-rexcellent.
No... you're not the only one stabbing himself with a pencil. The upside is, with my recently-acquired brain damage, I can see squant.
43rd Law of Computing: Anything that can go wr
How their brains interpret this data however is totally beyond explaination to those of us who have "normal" three colour vision.
.. and I can't even see the fourth one?! This is jacked up. I'm screwed -- I'll just give up on trying to match my clothing for women now.
Great... I couldn't understand how women could tell such subtle differences between the origianl 3 colors and now I've gotta try and figure out how the F they do it with 4
Justin Buist
Not Likely...
If memory serves, it is believed that only women are capable of having tetracromatic vision. Which (if memory serves) is normally seen as an extra shade of red. Tetracromatic people can often tell that items, which seem to match to ordinary people, don't. ie they can tell the difference between a true black ink and a cheap black ink made of cyan magenta and yellow inks.
Sadly Tetracromatic women generally will have color blind male children.
There is another primary color, but there's only this one old woman who can actually see it. Serious.
/Brian
(4/2)
colored light is light that only represents certain parts of the visible spectrum, adding more colors of light will get you closer the seeing the whole spectrum (white). On the other hand, colored pigments absorb certain wavelengths of light -- red (actually magenta) absorbs green light, blue (actually cyan) absorbs red light, and yellow (the only correct one) absorbs blue light. This is why adding more colors of pigment gets you closer to black (more wavelengths of light are absorbed and never reach your eye) you can acheive the primary colors of light with pigments by mixing any two primary pigments: cyan and yellow take away red and blue and you're left with green (this is how you get the "yellow and blue makes green seal"). magenta and yellow take away green and blue and you're left with red, magenta and cyan take away green and red and you're left with blue. tadah
`which fortune`
"Yeah, that thong looks great, hon. You look so thin and awesome. Yeah, definitely wear it to dinner tonight. I know it's 20 degrees outside, but you'll look great..."
Works well if the girlfriend is really thin and bluffs on the fat thing (by the way, the above dinner comment actually worked).
- I don't care if they globalize against free speech. All my best free thoughts are done in my head.
You try getting a bio/med student to go out in something unconservative.
- I don't care if they globalize against free speech. All my best free thoughts are done in my head.
But this is not a story of gene transplant for geeks for four color sight.
And there was a story a while back about a new basic taste being "discovered" (basic tastes being sweet, bitter salty), this being a flavor that is more common in asian foods, and is found in many oriental dishes.
But what about re-engineering the monitors to take advantage of the new discovery?
Check out the Vinny the Vampire comic strip
"It is a greater offense to steal men's labor, than their clothes"
Up to this point in time there have been only three primary colors, red, blue, and yellow, the basic building blocks of every rainbow. All other hues are made from combinations of these primaries. The secondary color green is formed from a mix of the primaries blue and yellow, for example. Violet from red and blue, and so on.
/. April Fool's joke.
This article contradicts itself. The three primary colors are not red, blue, and yellow, and in no way can they be. For light, or color by addition, the primary colors are red, green and blue, like the pixels on a TV or a computer monitor. These primary colors add only one color of light to an otherwise black background. Red and blue form magenta, blue and green form cyan, and red and green form yellow; those are the three secondary colors for light. All three of them form white light.
For color by subtraction, or the filtering of colors used in dyes, paints, inks, etc, the primary and secondary colors are reversed. The primary colors subtract, or filter out, one color of light from an otherwise white background. Magenta, cyan, and yellow are the three primaries. Magenta and cyan form blue, cyan and yellow form green (not blue and yellow like they teach in elementary school!), and magenta and yellow form red. All three of them combine to make black.
Also, come on people, "However, in a most interesting sidelight, pure squant has also proven to be the only color, primary or otherwise, to carry its own unique scent with it. The odor of squant is apparently also difficult to describe by comparison to known odors because it is a primary odor." This is obviously another
mmm...physics...
Why do we have more articles on April Fools day than any other day. Man this is bullshit.
I apologize for the unnecessary Steely Dan reference. I couldn't help myself.
Light is like any other wave (...) I don't know who lied to you, but it is indeed the frequency of the light signal being changed
I don't know who lied to _you_ =) it is clearly impossible, that the frequency of the light signal can change... you are right in the first part: it's like any other wave, so lets take sound for an example...
mix a 100 Hz tone with a 1000 Hz tone. you clearly understand, that you dont get a 1100 Hz tone as a result. you remain with two tones at the same time which you can distinguish with your ear. same is true for light... (except that you can't distinguish light with your ear ;)
you muddle up the time/amplitude and frequency/amplitude illustraton of waves.. a wave of 100 Hz for example is a sinus-curve in time/amplitude and a single point in frequency/amplitude. if you mix two waves you add the amplitude values for each time or for each frequency.. the result in a time/amplitude diagram is a different lookling wave, the result in frequency/amplitude are two single points, one at 100 Hz and one at 1000 Hz.
even in the time/amplitude diagram you can see, that the frequencies are not changed, if you mix a intense 100 Hz tone with a weak 1000 Hz tone: you can still see the 100 Hz sine wave, but with a frayed outline. if you look closer, you can see, that this frayed outline is the 1000 Hz sine wave forced to the path of the 100 Hz wave...
the reason you can mix light is indeed based on the three receptors you have on your retina. there is one for red, one for green and one for blue. each one has a range of frequencies they respond to with different intensity (like a bandpass filter).
a frequency between green and blue causes signals with little intensity in both receptors a pure green causes a strong signal in the green receptor. these signals are interpreted by a region in our brain and then we think: "hey man.. this is red !" at least some of us =)
int main (int argc, char** argv)
{
printf(stderr,"Unable to initialize RGBS plugin");
return 1;
}
Any technology distinguishable from magic, is insufficiently advanced.
Boy are all you people going to be surprised when you find out that all of the news posts are TRUE! now THAT would be a good april fools joke
With all this April 1st crap arround, I can't see Squant.
This sig intentionally left blank.
Light is like any other wave... When two waves cross paths the signals are added or subtracted from each other. I don't know who lied to you, but it is indeed the frequency of the light signal being changed. About the only thing out biology has to do with it is the range of light we can see. In other words, it is a mathematical proof that there are only three primary colors (or four for those that insist on counting lack of light as well). Any part of the spectrum that cannot be reproduced is a result of bad equiment that doesn't have the light frequeny quite right (like out monitors and TVs)
.. another colour for my girlfriend to wonder if she looks fat in.
Jarett