Succesfully removing banding

[Erik]

From time to time you prove that you're a real good guru.
Can't get enough of that.

By the way: I just remembered that when we were still at onlinedesignschool we had a thread abouit banding, on which I experimented with gradients of less than 256 pixels wide to show that there was indeed banding because of limited pixels to display the gradient.

I'm off to my hard disk. One second...

I did dig up this image. Now for the thread...

[{OZ}]

hrmmm.... lookie lookie... is there an end to learning? i dont think so...

thanks for the tipos guys

Erik, if I take your 256 pixels wide one and look at it in Photoshop; no banding.
If I look at that same file in this thread with a 16 bit color setting, I see banding.
That's one of the questions that's still open and I never found someone who could explain that too me, why it is that we sometimes notice banding in a browser and not if we look at that same file in Photoshop or a program like ACDSee. [confused] [confused] [confused] [confused]
That's the reason why I posted this trick, all for the purpose of web graphics only.

[theKeeper]

Aaa ok ya, for Web graphics then Gauss it could very well be a case of each browser rendering the images in their own specific ways. Browsers are known to be lousy at this, and do have limitations. And IE vs. NS is another thing altogether.
For instance... one may dither an image while the other may not.

I suggest you visit the sites of each browser and read-up on their specs. That may help you gain a more indepth understanding of this issue.

[Erik]

http://www.physics.ohio-state.edu/~w...afecolors.html

this is an article on the death of the websafe palette. It contains info.

A good article Erik, but sadly enough it only deals with web safe colors and my question has to do with Jpeg, not Gif. I think I will will do what Mark says and focus on the browser differences. Thanks anyway my Absurdian friend

[Erik]

I may not grasp the real problem yet, but I do remember Klaus Nordby posting at Talkgraphics about banding problems and 48 bit.
Fact is that when you install Win and have no video card driver installed, you see how ugly 16 colours can be.
In my opinion it is normal that 64.000 colours show banding.

JPG takes little squares and calculates a mean value for them. So if you don't have enough hues, the difference will quickly become apparant. Question of adding two weaknesses: not enough hues and mathematically calculated loss.

Does this have anything to do with the problem?

Erik, no offense, but I think you read too fast sometimes :P

I quote myself in 3 different posts:

"This problem is still one that amazes me, because even if these files look ok in Photoshop or ACDsee, they still show banding when you look at them in a web-browser"
"This banding problem is only visible in files viewed on the internet, never in the original."
"why it is that we sometimes notice banding in a browser and not if we look at that same file in Photoshop or a program like ACDSee"

But it's not a problem for me to explain it for you again, but first empty your thoughts [stuned] before you start reading and forget about websafe colors, GIF, CMYK and all the other things at the moment.

Ok, here we go:

I have a PC with 16 bit color settings
I open Photoshop
I create something with soft gradients in it.
I don't see banding
I save the file as JPEG
I look at the file again in Photoshop: no visible banding
I look at the file in ACDSee: no visible banding
I transfer the file to the web and look at it in Internet Explorer 5: I see banding...bingo!

One remark: even if I save the file as BMP, I still see the same amount of banding in my web browser.

I now use my trick with the noise to get rid of most banding problems in files that need to be published on the internet, but the final question that still stands is:
How is it possible that an ordinary JPEG file shows banding in my web browser, when it isn't visible in ACDSee or Photoshop?

I'm now going to do what Mark adviced and compare the different browser specifications to see if I find something, if not, no big deal, I just live with it. I already spent too much time on this problem

[theKeeper]

Oh ok Gauss... you're using a 16bit display huh?
Ok well that's where your problem is coming from then.
Sorry, but i was, for some reason, assuming you were using a 32bit display already. I don't think it was mentioned before that you used 16bit.

My advice about the browsers still stands if you're interested in that... but i can safely say that if you switch up to a 32bit display setting for your monitor, you won't see any banding.

Photoshop will usually, not always, display without banding; but that's depending on just how much banding there is in an image. And that point was explained real well by Erik in one of his first posts above.

That do ya any good then?

Yes Mark, it will do me some good, but sadly enough not for the people with a 16bit display viewing this web page. Web designers take in account different screen resolutions and browsers in their designs, but they forget about the fact that still numerous users are using a 16 bit display setting. The reason why I use 16 bit in some cases is to confront myself with this particular banding problem, something that would otherwise not be noticeable if I would set my display to 32 bit. The reason why I started this thread was because I sometimes publish my digital camera shots on the internet and I don't want to hear remarks all the time about banding, when it's not visible in the original photograph, either caused by me using a 32 bit setting on my side and viewers using 16 bit on their side or caused by some miraculous banding added by the different browsers.

Thanks for all your help Mark and Erik, I appreciate it