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What is Color Banding? And what is it not?

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Re: What is Color Banding? And what is it not?

#11

Post by im2w1l »

stefs wrote: post #10
Aardwolf wrote: post #2

Dithering is seen so often in 90's 256-color images, but why so rarely in the ugly banding of 24-bit RGB images?

I can't say for sure, but one of my guesses would be stability . By that I mean that the noise is acceptable for a single static image, because it doesn't change - but distracting in an animation if the dithering completely changes from frame to frame. I might be a non-issue - either not noticeable or not distracting - and the real reason is that people just don't see banding as a problem or that the rendering overhe…

Dithering seems to work for animated gifs.

Re: What is Color Banding? And what is it not?

#12

Post by kuschku »

im2w1l wrote: post #11
stefs wrote: post #10

Earlier quoted context omitted.

I can't say for sure, but one of my guesses would be stability . By that I mean that the noise is acceptable for a single static image, because it doesn't change - but distracting in an animation if the dithering completely changes from frame to frame. I might be a non-issue - either not noticeable or not distracting - and the real reason is that people just don't see banding as a problem or that the rendering overhe…

Dithering seems to work for animated gifs.

It’s very complicated there, too, though.

As this article [1] shows, even with animated gifs you have often unstable dithering with artifacts somewhere in the image.

[1] http://blog.pkh.me/p/21-high-quality-gif-with-ffmpeg.html

Re: What is Color Banding? And what is it not?

#13

Post by kuschku »

bluedino wrote: post #6
Aardwolf wrote: post #2

Dithering is seen so often in 90's 256-color images, but why so rarely in the ugly banding of 24-bit RGB images?

The alternatives to dithering a 256 color image both end up with undesired results. You can either create a palette specific to your image or application (which makes the rest of a multitasking system look like a tie-dye shirt), or have really, really ugly banding since you have a mere 256 colors to work with (minus reserved colors) instead of 2^24 24-bit images are 'good enough' and dithering would just add another…

And there is one alternative: 30bit (+alpha) colors.

But that’s currently only used by designers.

Re: What is Color Banding? And what is it not?

#14

Post by corysama »

hfsktr wrote: post #3

Every image on the page is broken for me (Chrome if it matters). I was hoping they would help understand what I was reading. Console is full of errors for where each image tried to load.

The page uses webp and webm. Don't know why your Chrome doesn't support that. Someone over in Reddit mentioned the same thing for an old version of Chromium.

Re: What is Color Banding? And what is it not?

#16

Post by simonschreibt »

hfsktr wrote: post #3

Every image on the page is broken for me (Chrome if it matters). I was hoping they would help understand what I was reading. Console is full of errors for where each image tried to load.

It seems that my site has problems when it's visited for example from behind a firewall which doesn't like my SSL-Proxy. I've heard that sometimes from people visiting the blog from work but at gome everything was fine...

Are you behind a firewall?

Re: What is Color Banding? And what is it not?

#17

Post by exDM69 »

kuschku wrote: post #13
bluedino wrote: post #6

Earlier quoted context omitted.

The alternatives to dithering a 256 color image both end up with undesired results. You can either create a palette specific to your image or application (which makes the rest of a multitasking system look like a tie-dye shirt), or have really, really ugly banding since you have a mere 256 colors to work with (minus reserved colors) instead of 2^24 24-bit images are 'good enough' and dithering would just add another…

And there is one alternative: 30bit (+alpha) colors. But that’s currently only used by designers.

30 bit color means 10 bits per channel equals 1024 discrete values. If you do a full-screen gradient from, say, red to black on a large resolution monitor, there will be color banding.

It's better than 24 bit color but doesn't solve the problem.

Re: What is Color Banding? And what is it not?

#18

Post by jaskerr »

hfsktr wrote: post #3

Every image on the page is broken for me (Chrome if it matters). I was hoping they would help understand what I was reading. Console is full of errors for where each image tried to load.

Do you use Privacy Badger or another blocker?

The markup loads images from seemingly local URLs:

  http://data.simonschreibt.de/gat055/intro_comic.png
but redirects to images stored at SSL-ACCOUNT.COM:

  https://ssl-account.com/data.simonschreibt.de/gat055/intro_comic.png
I reset Privacy Badger, and the assets loaded fine.

Re: What is Color Banding? And what is it not?

#19

Post by kuschku »

exDM69 wrote: post #17
kuschku wrote: post #13

Earlier quoted context omitted.

And there is one alternative: 30bit (+alpha) colors. But that’s currently only used by designers.

30 bit color means 10 bits per channel equals 1024 discrete values. If you do a full-screen gradient from, say, red to black on a large resolution monitor, there will be color banding. It's better than 24 bit color but doesn't solve the problem.

Current movies use 36 bit – that’s enough for 4K usually.

Re: What is Color Banding? And what is it not?

#20

Post by nitrogen »

oflordal wrote: post #15

The greyscale gradient animations that are meant to show banding are full of gif artifacts so they are not actually smooth gradients.

Is this an example of Poe's Law? GIF's palette size is 256, there are 256 shades of gray, so no GIF artifacts should be present. GIF doesn't have artifacts anyway; those would come from the dithering/palletization step before compression.
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