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Photograph banding

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User_Removed
31 Jan 2013 - 1:01 PM

I missed where you'd said pro photo Andy, I just saw RGB sorry about that

Is there somewhere you can upload a large high res low compression version of the image that you see banding in so Glenn and I can check it on our monitors. Bit concerned that the ePz uploads aren't telling the story.

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GlennH
GlennH  91918 forum posts France1 Constructive Critique Points
31 Jan 2013 - 1:12 PM


Quote: I missed where you'd said pro photo Andy, I just saw RGB sorry about that

Don't think he did say that, Chris, that was just me flailing around with random ideas!

Doesn't help that we're assessing a 600px photo - I can barely see the thing - although in the past it hasn't stopped my monitor from failing abysmally at rendering gradients smoothly. That in itself is a problem of course: the OP could do with more opinion in order to eliminate the monitor possibility (Ian said earlier that he could see no banding).

mikehit
mikehit  56444 forum posts United Kingdom9 Constructive Critique Points
31 Jan 2013 - 1:47 PM


Quote: when i tried to get rid of the dark edges i got banding not sure what i am doing wrong here,.

As I read it, the OP is not saying he sees banding on the original image, but only when he tries to lighten the sky. I saved it to my computer and opened in PSE9 and if I go into Adjust Lighting\Levels and drop the white point from 255 to 200 I start to see banding from the middle to top left.
This seems to me to be typical of dark areas where there is such a low level of information in a large area and banding is almost inevitable and although this will be made worse in a 600px JPEG it will also happen to some degree in the raw image as well depending on the camera (but as has been pointed out, the dcreen technology will also play a part).

GlennH
GlennH  91918 forum posts France1 Constructive Critique Points
31 Jan 2013 - 2:37 PM

Clearly I'm guilty of skim-reading here. Andy says he uses ProPhoto RGB in Photoshop as Chris mentioned, which will easily result in banding if you edit in 8-bit mode. The histogram doesn't really reflect that, but then subsequent fiddling can disguise a gappy histogram.

Yes, if you rake across an image with saturation and luminance clipping you'll see banding—more crudely transitioned in a compressed web photo. Not sure where that leads us?

samueldilworth
31 Jan 2013 - 6:53 PM

Another couple of thoughts on this.

First, your photo on page 1 doesn’t have an embedded profile, so it looks super-saturated on my wide-gamut display. You should embed a profile in web photos for the sake of us poor Safari users.

I see very little banding in the photo in its super-saturated state, and even less (nil, basically) after assigning an sRGB profile to it. Unless you’re much pickier than me, I doubt you’d complain about the amount of banding visible at my end, so I suppose the problem must be at your end (display, GPU settings, calibration/profile, etc. Your workflow must be okay, at least for this particular photo, since the photo looks okay to me).

In any case, 14-bit raw is the best you can do when taking the photo, and that will never introduce posterisation on your D300S: the noise, even with optimum exposure at base ISO, is high enough compared to the bit-depth to effectively dither the signal. Even if you go wild with your post-processing you’ll never see banding attributable to the 14 bits in your raw file; you’ll just ‘unearth a load of noise’, as Glenn says, or – at worst – provoke banding attributable to your workflow. See this page for a great explanation of how noise dithers tonal transitions (especially the first two mouse-over images).

Which leads me to another thing. You said that sharpening reduces the banding. Sharpening accentuates noise, so it makes sense that it reduces banding: it effectively dithers the problematic tonal transitions.

In addition, more noise (from sharpening, for example) might cause your JPEG compressor to allocate more bits to the JPEG, which might reduce posterisation from JPEG compression. However, I don’t think JPEG artefacts are the problem here, since I don’t see significant posterisation at my end.

Steve-T
Steve-T  751 forum posts England66 Constructive Critique Points
2 Feb 2013 - 11:13 AM

This is an informed article on banding which may help
http://support.phaseone.com/KBFiles/1385/1/ColorBanding.pdf

Steve

Last Modified By Steve-T at 2 Feb 2013 - 11:13 AM
rhol2
rhol2 e2 Member 3296 forum postsrhol2 vcard United Kingdom1 Constructive Critique Points
3 Feb 2013 - 8:21 AM


Quote: This is an informed article on banding which may help
http://support.phaseone.com/KBFiles/1385/1/ColorBanding.pdf

Steve

Thanks for the link, Steve..an interesting and informative article.

Though I've not had the problem yet, it's useful if the need arrives.

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