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Comment by JoelSutherland | Hacker News Reader

A subtle point this article makes is that pure black doesn't exist as displayed by your monitor. #000 is just the darkest value your monitor can display.

Across monitors, contrast ratio can vary by over an order of magnitude.

I'm not saying I don't prefer black, but I don't enjoy reading black text on a white background on an OLED phone in a dark room.

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If #000 is not pure black but the darkest value the monitor can display then that defeats the purpose of his article, doesn't it?

Plus, he played Halo in high school? Geez, I'm not young. He meant to say Doom right?

Halo apparently released in 2001. My wife graduated in 2002, so she could have (and might have) played some Halo in High school. She's 28, so not that young.

I played Doom in Highschool myself. Late(ish) highschool (class of '95 here)

Sure, it's not "pure" black, but his argument is more that the average monitor's #000 text on a #fff background still has too much contrast for comfortable reading.

But I didn't get much out of the article discussing the idea of black on white for text. The majority of his post was about the color of elements on the page. I'm not saying I disagree with his point, but the talk about pure black when it doesn't exist in that context makes it seem strangely written. Looking at it in terms of contrast then it makes with the thought of grays versus black.

Out of curiosity: are there any objects that are "pure black"? (i.e. 100% absorption of the entire visible spectrum of light)

My naive guess is that the only way to have pure "black" is an absence of light (ex: deep caves, deep sea, etc)

I remember reading (a very long time ago) that the best way of getting close to pure black was to take a horn (of the type used to store gunpowder back when flintlocks were considered modern weapons) and hold the open end over a smokey candle until the entire inside was covered in lamp black. The combination of the very non-reflective lamp black and the curved shape of the interior ensured that almost all the light entering didn't leave.

Anything close to a perfect black body would be close to true black.

Thousands of feet of water are pretty good at absorbing and reflecting all electromagnetic waves before they reach the bottom, but because it's reflective it's not a black body.

I don't think you could actually see that pure black. Problem is, that there's always some noise in the wiring that goes from the eyes to the brain, and you'll end up seeing some random coloured patches every now and then.

A black body is an idealized physical body that absorbs all incident electromagnetic radiation, regardless of frequency or angle of incidence.

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

Here's an article about a material that absorbs 99.9% of light http://news.rpi.edu/update.do?artcenterkey=2393

Thanks! Both the camera and SEM photos reminded me of my grad school days doing CNT research :). Kind of serendipitous and awesome to find out that I had already seen the "very very black" material with my own eyes just four years ago!

Not sure if anyone has beaten them since, but a few years back my alma mater came up with the darkest man-made material to date.

http://news.rpi.edu/update.do?artcenterkey=2393

From the outside, a black hole would be "pure black", but it's probably really bright on the inside.

There's not really an inside of a black hole anyway. The black hole it self is nothing but a tiny spot yet massive in weight. There's an inside the event horizon though. Commonly people like to refer to the size of the event horizon as the size of the black hole, so that might be the "inside". In that case it's hard to tell whether it's bright or not. My guess is that it's certainly brighter looking outside than towards the singularity, which should be black, because there's no light coming from that direction whatsoever, since it all gets swallowed. Then again I'm no physicist, so I'm not really qualified to make any claims here.

"There's not really an inside of a black hole anyway. The black hole it self is nothing but a tiny spot yet massive in weight."

We really don't know that. All our theories fail around black holes so we can only speculate what's going on in there. And even speculation is limited by our current mental capacity, which may be insufficient to understand/explain what's going inside black holes.

There are actually a several effects that can make a 'black' hole rather bright from sufficient distance. Hawking radiation, gravitational lensing, frame-dragging, and an accretion disk can create some ridiculousness energetic objects.

As pure black is the absence of light, nobody can claim to directly see pure black. The detection of pure black goes like this, 'Nothing to see here, moving along'.

Your comment reminded me of this video on black holes: https://www.youtube.com/watch?v=GYKyt3C0oT4

Activated charcoal powder is the closest thing I've ever seen to pure black.

There's nothing that quite reaches 100%, but there are a few things that get very very close. I think the current best is to stand a bunch of nanotubes on end.

I believe everything has the capacity to reflect some light except a black hole, which is able to trap that too[1].

But as far as the human eye can detect, there are probably a lot of things (whether real or artificial) that are indistinguishable from this 'true black'.

[1] Black holes can trap light outside the visible range; I'm not sure if there's something that can trap the entire visible range but not everything outside it.

It's actually a subtle but important point this article conspicuously does NOT make.

Apart from that, I agree. Except that your lack of enjoyment reading from that OLED phone has not much to do with the use of pure black and everything with the use of pure white.

It's unpleasant reading #666 text on #fff background in a dark room just as much, because nobody likes looking into a bright lamp in a dark room.

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