How the hell did they get 1024 colors out of a 1981 PC?



Well, when you put it THAT way…!


So am I right about this. If this guy went back in a time machine to 1981 he could make a computer do this?

That’s just amazing.


Yup. The video is a direct recording from a physical IBM 5150 with no anachronistic expansions, and the color tricks depend entirely on the quirks of the CGA hardware and NTSC encoding (so it would have been, if anything, easier to find the hardware to demonstrate this in 1981 than today).

And it is rather amazing. :slight_smile:


I have to echo Trixter, “HOLY F!@#$%G SHIT. WOW.”

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Right, I think @beschizza misspoke. This wasn’t written for laypersons of the technology.

Er, the page wasn’t written for nontechnical laypersons.

From the page:

“Fair warning: the ‘target audience’ for this writeup is people who may not be overly familiar with CGA, and/or come from other demo platforms.”

In other words, the target audience is for those who are at least somewhat familiar with CGA. This isn’t for laypersons who’ve never heard of it before.

That said, @beschizza, if you’d like to translate the info into something that laypersons can grasp, that’d be great! :smile:

The Microsoft Metro UI (Modern UI, Windows 8+ tiles) is getting CGA colors out of 32-bit display hardware, maybe these guys are using an inverse of that process?


If you’ve ever looked closely at text on an old CRT or TV used for an Atari computer or game console, you might have noticed all the tiny little fringe colors on the edges of the letters.

This is kind of like how when you take a picture with a digital camera, you might see color fringing like this (see the purple):

This was considered an aberration (“fringing” and “bleeding”) back in the day for computer text, but now this guy is exploiting those little aberrations to create more colors to use with the old computer.

The genius is that he’s taking an aberration and retrofitting it into an innovation.


Precisely. And I’m the one that gave him the idea! I’m so proud.

How did that happen?

Who knows! Alternate timeline? Time travel is too complicated for me.



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I saw this on Sunday and was mesmerized. I tried to explain to my 13 year old son why it was so amazing but I don’t think he can fully understand the significance.

Now my only guess is that the machine can’t handle doing the graphics and the mod music at the same time.

Could they port FCEUX to work on that?

“By carefully picking an amenable hardware setup and manipulating the electrical signal output to systematically control its chromatic aberrations, they were then able to cast haruspex and kill voldemort”


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That dog is clearly where the soul of Ron Swanson has migrated.


If you’re old enough to remember the original hardware, that is just mind blowing.

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I see Charlie Stross has been hired to do the Potter updates.


It’s a really clever technique! The impressive part isn’t so much that they’re exploiting an NTSC signal by alternating colours, because that was already commonplace by the early 80s on more graphically powerful systems and is certainly well known by now.

The clever part is that they’re essentially inventing a new graphics mode by using the top couple of pixels of the ‘U’ and ‘!!’ characters to get alternating pixels.

To be able to use just those two row of pixels they have to use an undocumented text mode that has 100 rows per screen, on a screen only 200 pixels tall.

It’s a hack of a hack of a hack. Wonderful!