Help w/ banding

[matthew_hull]

For the first time in a great while, when I tried to Save-for-Web using Photoshop CS the resultant JPEG file had significant banding on the smooth area to the left. I managed to remove it (mostly, see below) by saving the file as a GIF instead. However, I'm not entirely happy with the results. I tried Adding Noise, and that helped, but it also added noise when I really didn't want noise.

Does anyone have any advice on avoiding Banding when saving to small web files?

 

[ukcatfan]

Don't use that feature and just do the re-sizing yourself. I am pretty sure the save for web function adds a lot of compression and that is what causes the banding. Or you could use Irfanview. I believe it is the easiest tool to use when batch re-sizing for web and it allows the customization of the size and compression.

 

[matthew_hull]

Thank you very much for your insights. Sometimes the obvious escapes me -- the do-it-yourself resize produced the best results, at the cost of filesize (larger files). I did not know that IrfanView could do such things. I have always used it as a backup file viewer and as a quick tool to see the EXIF. However, it addressed the problem by adding noise as well, with rather good results, I must say. However, the GIF pattern-dither (to my eyes) is still the best compromise.

Does anyone see "significant" banding (I know, I know) in the posted image, and if so, what web-browser are you using?

Is the pattern-dither (the slight checkerbox look, or perhaps the ASCII-art look) in the background a significant distraction, or am I obsessing? It is most noticable near the eyebrow.

Am I right to suspect that the image looks much better on my screen than it does on someone elses, because the image save was optimized for my existing color-palette?

 

[Code]

Can you post the JPG so we can see what you're referring to? GIF is definitely not the way to go as GIFs are limited to 256 colors.. the "banding" you see in the GIF is called dithering, which is what it does to smooth transitions to compensate for the limited color palette.

 

[matthew_hull]

The manually-resized JPEG has been posted to a temp scatch area.

Can you post the JPG so we can see what you're referring to? GIF is definitely not the way to go as GIFs are limited to 256 colors.. the "banding" you see in the GIF is called dithering, which is what it does to smooth transitions to compensate for the limited color palette.

 

[Groucho]

FWIW, I've also found Irfanview to produce much smaller files than Adobe. I can have Lightroom resize my photos to 1280x1024 before uploading, or export them full-size then have Irfanview do a batch job to resize them. Both are set to 90% quality. The Irfanview files are about half the size, still have the exif data, and I certainly can't see any difference in image quality.

 

[Code]

I don't see any banding, just some noise?

 

[matthew_hull]

It is also probably important to mention that I am using MS-Windows XP, a large-screen LCD display, and an old graphics controller that necessitates using Color-Quality Medium (16-bit) setting (due to memory problems). The banding is not apparent when set at Color-Quality Highest (32-bit).

 

[matthew_hull]

Code, et.al.:
So for your setup, is the JPEG or the GIF the more pleasing rendition?

I don't see any banding, just some noise?

 

[Groucho]

It is also probably important to mention that I am using MS-Windows XP, a large-screen LCD display, and an old graphics controller that necessitates using Color-Quality Medium (16-bit) setting (due to memory problems). The banding is not apparent when set at Color-Quality Highest (32-bit).

Like the others, I don't see the banding. If you're seeing it at 16-bit, that's not a problem with the image, it's a problem with looking at things in 16-bit. I would hop right on eBay and buy a video card that can consistently do 32-bit... heck, you can buy brand-new ones for probably $30 or so. I think I paid $35 for my ATI 2400 HD that I run my home theater off of.

I would say that you're seeing banding because there's such a gradient of color there that the 16-bit is forced to drop a lot of colors. If other conversions work OK, then maybe Adobe is saving the colors in a slightly different way that Windows deals with differently when viewing at a lower color palette - and maybe others are tossing colors that don't exist in the particular photo so it displays better.

I can say that if I view things at 16-bit, I see all sorts of bad color gradations in a ton of pics.

 

[matthew_hull]

Thanks, Groucho, that is indeed just what I did. I went online and bought a new video card, altho for nowhere near that fabulous $35 price. Swapping a video card isn't my idea of fun, but I agree that with the new large monitor that it has to be done. Thanks for helping me get to the bottom of this.

 

[dpic]

Posterization occurs when there aren't enough colors to smoothly show a gradient. Without a doubt looking at this image with a 16-bit display will make it much more pronounced. It still is slightly visible in 32 bit, but you have to look close.