Comment by jiggawatts | Hacker News Reader

Comment by jiggawatts | Hacker News Reader

One of the worst "ossifications" of non-standards is the notion that colour is three channels of 0..255, one each for red, green, and blue. Combined with the incorrect assumption that the scale is linear[1], and you have a perfect combination for a Dunning-Kruger effect: A bunch of programmers[2] who think they've figured out "graphics", but haven't even begun to understand how any of it works. Not any of: light, display technology, colour standards, or even the human eye.

A short list of falsehoods programmers believe about vision:

- sRGB is the only graphics standard.

- Monitors are actually sRGB and follow that standard.

- Colour intensities are on a linear scale.

- White is 0x00FFFFFF or 255,255,255

- 50% Grey is half of the above: 127,127,127.

- Blending colours is just a matter of linear interpolation.

- Red, green, and blue have a single consistent definition.

- 8 bits is enough for each colour channel.

- Okay, 10 bits is enough.

- 12 bits is enough, surely.

- 0 means black.

- Okay, 16 means black on televisions.

- Fine, black can have different levels in different standards, but it's always clear which level is black.

- At least the white level is consistently defined.

[1] Narrator: it's not even remotely linear.

[2] Including myself until recently.

> White is 0x00FFFFFF or 255,255,255

Calling this a falsehood isn't even beginning to describe the problem: - does not distinguish between a white surface (reflects all light) and a white emitter (emits blackbody radiation in a specific temperature range) - there is no maximum intensity for emitted light, but there is a maximum for reflection - RGB (255,255,255) does not produce a blackbody curve -- though it can cause the same reaction as a blackbody curve for people with exactly three working cone types. This point may be wrong on this list because it may be thought of as a solved problem. - RGB (255,255,255) does not specify the temperature - that is before monitors even start being imperfect

Oh, and a general one: An emitted color (e.g. monitor) and a reflected color (e.g. printout) cannot be the "same", ever, because only the latter depends on how it is illuminated.

What about RGB (256, 256, 256) though?

Edit: Oops, I read "there is a maximum for reflection - RGB (255,255,255)" as one statement rather than two fragments but I still like my response. :P

Light speed is too slow!

I made the same mistake again as always -- writing as bullet points and not looking at it after submitting :(

I always understood OxFFFFFF to be “give me all you’ve got”. Of course a quasar is going to be able to emit more powerful photons than a 90s CRT. But if said quasar had a GUI, 0xFFFFFF would mean “master blaster”, and the same for the old screen. My expectation as a programmer was never that the colors would have any semblance of “realism” or “uniformity”, and to expect variance from machine to machine. Perhaps since I have not involved myself with photography software and kept my budget for displays below the thousands-per-unit this has held true so far

What I tried to say by that is that "give me all you've got" is the only kind of maximum a screen can do, and a brighter screen (or a quasar) will be brighter. OTOH, "reflect everything" is the absolute maximum for reflection, and no other object will top that.

> OTOH, "reflect everything" is the absolute maximum for reflection, and no other object will top that.

Maybe some old night scopes with photon amplifiers could be coaxed into making "over 100% reflective" mirrors? A fun idea to reasearch.

Any monitor can simulate HDR ("brighter than 255") images by simply darkening the rest of the picture around them.

Also, in TVs it's 16-235 not 0-255. They're not even 8-bit!

> An emitted color (e.g. monitor) and a reflected color (e.g. printout) cannot be the "same", ever, because only the latter depends on how it is illuminated.

Surely there is a case when the light coming into your eye is the same for both? If the printout is lit by the monitor wouldn't it be the same?

The colors can be the 'same' under a specific illumination condition. Standards that help make sure prints look like your screen specify the illumination condition of viewing, and then demand the spectrum radiating from the screen and paper 'look' the same.

Often this is a daylight lamp shining on the paper with a specified intensity, in an otherwise dark room (I believe) compared to watching the screen in a specific ambient light (again daylight with a given intensity).

There is sometimes the expectation to get a printout that looks the same as the image on screen in any illuminating condition. The whole process of designing printed material (or, say, a passive billboard) on a computer has to constantly avoid making that assumption.

> - Blending colours is just a matter of linear interpolation.

I recall there being a particularly contentious bug report for Adobe Photoshop eight or nine years ago. The original thread is here: https://community.adobe.com/t5/photoshop-ecosystem-ideas/p-g... - but all the users have been replaced by "FeedbackCommunityMember", so it's a bit hard to figure out who is talking to who (perhaps someone can find a properly archived url).

In any case, an Adobe product person was unbelievably stubborn about their assumption there is just a single way colours can blend one to another, and that all the other ways couldn't possibly be desirable. It was pretty hard to read.

That is a pretty wild thread to read. Also funny to note the update- > Special thanks to @bennettf96052341 for his gracious feedback

I remember a youtube video from years ago explaining this problem with photoshop's gradient tool (and other naive implementations), but I can't find it now.

Colors are hard.

The first one would be "colors exist as a physical concept". They do not.

There is no relationship between the physical nature of light and what we call "color". A wave has a frequency. There is no concept of "color" associated to a wave.

We statistically put names on some convoluted detector/brain transformations and everyone does the transformation differently. This is why most of the people agree that a tomato is "red".

As an ex-physicist, I hate to speak about colors in a physical context (and yes, we have charts that show that higher frequencies are "blue" and lower ones "red"). Color is a biological concept and should stay that way.

And then, as a farther, I have to explain to my children the convoluted course on colors in high school in France.

Sorry, I had to let off some steam.

This is navel gazing along the lines of cocktail-fueled debates over a tree falling in a forest. Does light still have a color if no one is around to see it?

Fundamentally these words have lots of reasonable wiggle room to expand or narrow their definitions. Still, lots of technical domains would like to be explicit about what is meant, especially when reusing common words, which is why man invented the glossary.

Unfortunately this hasn't stopped endless argumentation over whether a tomato is a fruit or a vegetable. For whatever reason, it's often presumed that the definition of fruit used in botany has "won", even though botany has nothing to tell us about what a vegetable is or how to distinguish one from a fruit.

I am not sure I understand your point.

On the one hand you have light waves that hit some receptors in the eye. These receptors (various kinds) sensitive to frequencies according to a function. This creates a specific signal that is analyzed by the brain which assigns a "color" to that signal.

Everyone's, to some extent, functions are different. There is a general trend so most people agree on "colors". When you are colorblind, the functions differ drastically (or are just flat).

This is why "color" is a biological concept (same as, say, "pain") to which we are desperately trying to attach three or four numbers (or, worse, a wavelength)

450 THz electromagnetic waves are unambiguously red light, you can nitpick about the shade of red, how people perceive it, etc... but it is red. It may look differently to colorblind people, or dogs, but it is red. The electromagnetic spectrum of frequencies just lower than red is called infra-red, don't tell me that physicists don't talk about infrared.

If you look up some colors in Wolfram-Alpha you will have precise ranges of frequencies, I am not sure they are officially defined ranges, but colors, at least pure colors correspond to physical quantities.

There is some overlap with biology, and there are some colors are special (brown, purple, ...) and can't be defined by a single frequency. Then you can introduce color perception, and how very real and physical red photons are perceived as red, why a combination of red and green photons are perceived the same way as yellow photons and how spectrometers reveal the difference, and how there are no purple photons.

Composite colors are a bit more complicated, you need to add a bit of math (namely, a color space) in order to formally define them from physical quantities, but saying that it is not a physical concept is going a bit far.

No need to make physics more abstract than it is. Because what's next? Temperature is not a physical concept because we don't all agree on how hot something is? Like color, temperature is a well defined physical concept that is based on our perception.

I think with color, it’s important to appreciate the irregularity that exists in this domain. You’re right that colors are defined as ranges of wavelengths or blends of ranges of wavelengths. And so there is a mathematical component to color. Yet, the mathematical view of color is imperfect if you ultimately are concerned with the perceptual end result. People are always trying to create better, more perceptually accurate color spaces, but all of them have their issues and weird corners where the adjusting the values in a certain direction doesn’t yield the expected result.

In that case, what is the frequency of the light needed to create "salmon"?

Or in other words: is "salmon", "fuschia" and other colors located on the frequency spectrum? If so - why do we have zillions of color spaces instead of just a simple frequency? (or wavelength)

At the moment when you introduce color spaces, you start accounting for how our eye receptors are sensitive to frequencies and leave the realms of physics (mostly because the receptors differ from person to person)

When you take a 450 THz wave, you say it it is "unambiguously red" because it is what happens to be the word for the signal which is triggered by that wave. In most of the people. Roughly the same way.

What I am trying to say here is that a color is a concept as well defined as "pain". You can have all sorts of measures, but none is strict.

Finally, there are no "red photons", or green or blue (you mention them) - this simply does not exist at all as a concept.

> A wave has a frequency. There is no concept of "color" associated to a wave.

Funny because when I explained radiant heat to my daughter I used it as an example of light, but infrared is a color we can’t see (but we can feel the light the same way we feel the sun on our skin). She asked about other colors and I went into ultra violet, X rays (a color to which we are transparent), gamma rays, and so on.

Yes, you described her how a wave interacts with her body and creates sensations (heat, colors, ...).

This is absolutely true, but the wave does not carry any of these sensations on its own, it is its interaction with sensors/receptors in her body that creates it.

Like I said elsewhere, a color is like pain - a needle does not have any "pain" in it and a couch hit with a needle will not create "pain".

Also:

- Pixels are squares

- Pixels are as wide as they are tall

- Limiting the colour gradient across an area will make it look smooth (Mach banding yay)

- The number of bytes in a line of an image is bits_per_pixel * pixels_per_line

- High frame rate means smooth animation

- Transitioning from an RGBI value of one to zero is instantaneous.

- If not instantaneous, it’s linear

- The phosphor’s response to the gun intensity is linear.

Forgot one:

- An isolated lot pixel on a CRT is a circle.

This would make for an excellent blog post

I would, if I thought it would make a difference. It won't.

I just bought a new 2022 model flagship television, and its colour management is very visibly broken![1] My partner, who knows nothing about colour standards mentioned that she thought the colours were "off" within minutes of using it.

This is the good brand and model according to reviews. I've seen the other brands in the store, and they're markedly worse.

Like... stupidly bad. Garish beyond belief. People looking like they're wearing clown makeup. Normal colours looking like neon tubes.

Are most people colour blind? Am I weird? Did I marry someone equally weird?

Or is it a mistake to just say: red = 0xFF0000, commit the code, and call it a day?

It's probably just me. Never mind.

[1] Unless I connect an Apple TV to it, on which nothing is broken. It's amazing that only one company on this planet is able to comprehend colour. Every other organisation, propriety limited, corporation, and charity is staffed entirely by colourblind people or robots that see only black and white.

I can't even tell the difference between the color settings on my phone or TV. I am not colorblind, I pass those tests. I think maybe I have spent so much time staring at screens in my life that my brain has internalized rgb.

One of the most enlightening things for me long ago was trying to write a converter between wavelength and rgb value. It led to all the right questions.

Ultimately I still dont understand color perception. It is hideously complex. But also so fascinating. The mothers of colorblind men are often tetrachromatic. I really wonder what TV's look like to them, since they assume 3 normal frequency responses.

Well this is a thing that exists after all:

https://en.wikipedia.org/wiki/Tetrachromacy

Garishness on new TVs also comes from the "soap opera effect", caused by motion smoothing, which is enabled on every new TV I've seen (and which tends to reset itself every few months on my home TV). Turning that off makes everything so much better.

On my TV it's called "perfect motion" and it's terrible.

God made movies 24 fps for a reason.

Moving pictures can look strange (juddery) on LCD/OLED TVs without either a little motion smoothing or black frame insertion. They were made to be shown on a flickering projector after all.

Also, you see people saying "motion smoothing needs to be turned off to respect the artist's intent" but have you seen what those people get up to? It's like a moral obligation to disrespect them.

The problem with the color balance on most TVs is that the red channel has been turned way up. The reason manufacturers do this is it makes the picture stand out when TVs are displayed in a big line. A properly balanced TV looks bland in comparison. And most people don’t realize this and have just gotten used to the way things look.

There are other things to do, but usually just turning down red significantly gets you a lot of the way there for minimal effort.

Check your TV's settings. Most, if not all, TVs ship in some sort of display demo mode that jacks up the contrast and sharpness and does all kinds of horrible things to make it stand out in the environment of a show floor. On Samsung, it's called "Dynamic" last I knew, but other euphemisms are used by the other manufacturers. I call it "Claw Your Eyes Out Mode", but that's obviously just me.

Generally if you tune your TV to any other "mode" as a base mode, you'll get much better colors. At first it'll look dull next to Claw Your Eyes Out Mode, but stick with it a bit and your eyes will rapidly come to appreciate not being clawed out.

You can also generally find suggested settings for your TV from people who calibrate them with professional tools. You'll see them also say you shouldn't just take them directly because your TV may be different, but from my point of view, the upgrade from CYEOM to "calibrated based on the same model even if it is a different instance" is probably about 99% of the upgrade you can expect and I don't consider the remaining single-percent upgrades that may be theoretically possible to be worth the effort required.

I tend to like “game mode”, where the TV does as little processing it can só the image is minimally delayed. It also has the side effect the TV doesn’t try to “improve” anything.

> This is the good brand and model according to reviews

Any half-decent review should mention both out-of-the-box colors and "calibrated" colors, or colors in different modes.

Its kinda open secret that the default modes and settings of TVs are absolute bullshit. Most "good" TVs can be adjusted to decent color reproduction (albeit not always without compromises).

It feels like the tide might be turning; stuff like "Filmmaker Mode(tm)" is popping up, and generally people are becoming more aware of the stuff. But that is not without its downsides, just recently there was a story about how big-box stores are price gouging unaware consumers with their "calibration" services that they are very aggressively selling with TVs.

> Unless I connect an Apple TV to it, on which nothing is broken.

Did you calibrate the Apple TV using an iPhone? (e.g., https://www.macworld.com/article/344476/iphone-apple-tv-colo...)

Look up the correct settings on https://www.rtings.com/tv/reviews and set those, it'll be fine. Or watch everything in Dolby Vision, which should already be right.

If you didn't buy an LG OLED, I also recommend returning it and getting one of those.

And Pink isnt even real :-)

I once met her and I can tell you she exists.

That's the thing about Dunning-Kruger. It's always invisible. You could be surrounded by a herd of 100-ton Dunning-Krugers and never know it.

It’s only invisible from the inside. From the outside it’s painfully obvious.

Unless it's shared, of course.

Then you are still inside.

Actually, the correct plural is "Dunnings-Kruger".

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