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banding... more complex the longer i work on the t

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  #21  
Old 12-08-2008, 07:19 PM
pixelzombie pixelzombie is offline
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Re: banding... more complex the longer i work on t

can you post a portion of the file that appears to have banding on the screen?
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  #22  
Old 12-09-2008, 10:43 AM
tomasz.k tomasz.k is offline
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Re: banding... more complex the longer i work on t

Here is a link to the photo I was referring to. It's just a part of the background, but I can't show any more unfortunately, it hasn't been published yet.

On the right hand side I drew the areas where I see green and magenta

http://www.houseofretouching.com/Download/banding.tif

and here is a link for the file just after developing
has even worse banding at least on my screen

http://www.houseofretouching.com/Dow...anding_dev.tif

Hope you see the same... I checked to make sure and our monitors have 12bit LUT and 12 bit internal processing, so upgrading to Eizo CG should make the difference you were talking about Tommy.
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  #23  
Old 12-09-2008, 12:10 PM
tomasz.k tomasz.k is offline
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Re: banding... more complex the longer i work on t

Quote:
Originally Posted by TommyO View Post
I am thinking that the problem is a combination of the larger working color space (AdobeRGB), damage to the histogram due to various edits, low final image bit depth (8-bit), and somewhat low monitor bit depth (12 bit internal LUT). So, it may simply be unavoidable unless you change one of the above mentioned elements.
The thing is though, that we develop to Adobe 1998 from C1 and try not to do too much curve work in PS. So if what comes out of C1 has banding on an average screen I guess we have to retouch it somehow even if it's not there. After all the image will surely be printed but it usually will also end up in the web at some point and none of our photographers want to hear the "it will look good in print" theory

Quote:
Originally Posted by TommyO View Post
Since you mentioned it is seen in different areas at different times, I cannot agree with your second point, having to retouch it out. You're just chasing a moving target, accomplishing nothing if the posterization is going to move again.
Yes, but again what can we say to the client in that case... but it is definately a point that we ought to be able to tell weather what we see on screen will print that way or is just a case of our hardware misleading display, so I guess we will have to upgrade very soon from our 12bit LUT and 12 bit processing Necs to Eizo CG series, but they also have 12 bit LUT, it's the processing they have at 16bit

Quote:
Originally Posted by TommyO View Post
It also sounds like some testing is in order. Create an image with subtle gradations in AdobeRGB. (Just download a standard output profile.) Save output files with graduated editing problems and check on your hardware.
Sorry Tommy I don't quite follow this part?
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  #24  
Old 12-09-2008, 12:30 PM
tomasz.k tomasz.k is offline
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Re: banding... more complex the longer i work on t

I decided to check both of these links at home on a 4 year old imac which hasn't been calibrated for half a year (so I would say it's a standard users computer)and ... I can see less banding here then on our much more expensive studio monitors. It is there though in the same places, but much less saturated.
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  #25  
Old 12-09-2008, 01:04 PM
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stopa stopa is offline
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Re: banding... more complex the longer i work on t

i can see it even on my old CRT

Last edited by stopa; 12-09-2008 at 01:11 PM.
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  #26  
Old 12-09-2008, 05:25 PM
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TommyO TommyO is offline
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Re: banding... more complex the longer i work on t

Tomasz,
I'm starting to think it has little to do with hardware and a lot to do with variations in human vision.

I see no posterization at all. However, I do see subtle variations in color and tonality that simply look like intentional variation in the background. The variations are very tricky to the eye, as well as to the LCD display and lighting conditions.

My eyes are very evenly sensitive to all three primary colors. Other peoples' do vary a great deal. Anyone more sensitive to red or green will certainly see more posterization due to the component colors in your particular background. (See attached thumbnail)

Since the variations are very subtle, low bit hardware could certainly enhance it and be a factor in the degree in which your eyes perceive it.

I did see some clipping in the shadows of the clothing, as well as in the blues. But, that should not affect the background posterization issue.

In the end, I think you have chosen a background color that is tricky. Some people will see it as a soft blend, similar to a brownish, greenish, gray color. Others are going to see posterization on those zones where the reds and greens shift, simply due to their own eyes being more sensitive to those colors. On the thumbnail, I chose a 3x3 average since most adjacent pixels were very similar in value. However, while my eyes can see the hue shift from just a few % in the next zone, I don't perceive it as posterization/banding.... just a subtle shift. It would be interesting to see what a sample of 10 or more people see on your monitor, with no hint of what they should expect to see.
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File Type: jpg banding_dev_copy.jpg (147.1 KB, 30 views)
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  #27  
Old 12-09-2008, 07:15 PM
pixelzombie pixelzombie is offline
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Re: banding... more complex the longer i work on t

i looked at both images on apple and eizo monitors and that's not what i would call banding..i see that as being digital artifacts from the cameras sensor, it also happens with film images that are scanned on low end drum scanners..the dynamic range is just too high for the sensor to record accurately if that makes sense...
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  #28  
Old 12-09-2008, 11:24 PM
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stopa stopa is offline
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Re: banding... more complex the longer i work on t

Notice that I have foresee that tomasz.k have problem with semi-black background. It is common thing, and as I said before it is a raw arithmetic.
Tomasz.K work in conformity with the regulations, this is what you can achieve in 8bit scale.
And I would be surprised if this thing will be perceptible on A4+ coated cover.
Unfortunately from my experience I can said, that the simplest things are as heaviest (time consuming) as possible!

-I think that you can add some noise, if you wish.

Last edited by stopa; 12-10-2008 at 01:07 AM.
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  #29  
Old 12-10-2008, 11:16 AM
neumanns neumanns is offline
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Re: banding... more complex the longer i work on t

I am on a low grade monitor, But I do not see banding. What I see is color variation in groups if that makes any sense. To me banding is uniform.

Do you get the files completly untouched. Straight from camera with no styles, contrast, sharpening, Etc.... From looking at the undeveloped tiff there seems to be some contrast issues. I only shoot a canon 40D but if you look at 100% view of the clothing there seems to be some extreme variations from neighboring pixals in areas where there should be a softer transition.(lighting alone should not cause this abrupt of change)

My guess has changed...I think the problem stems from post processing before conversion to tiff. Possable causes could be curves, contrast, or "in camera" style settings.

I would be surprised if a camera raw file with no "presets" showed the problem as prominent.

Last edited by neumanns; 12-10-2008 at 11:31 AM.
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  #30  
Old 12-10-2008, 12:33 PM
tomasz.k tomasz.k is offline
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Re: banding... more complex the longer i work on t

I'm back. Too much to do today to answer earlier.
So you think it's not banding, do you? I must admit that a lot of the files we work on are developed in C1 with channel work on them (and cutting off channels often creates a mess, but the effects look astonishing in my opinion). Some of these "color variations" (for me still banding) might be very subtle but they are obviously faults we have to mend in the retouching stage.

More then once we experimented weather doing the correction in PS would not give lesser banding, but that road always fails... and I'm happy about it as I do prefer to think of the RAW as the negative out of which I have to push out as much as possible before altering it in ps.

and so thank you all for the help. From these posts I have learned a lot and if I come up with a different solution or understanding of the problem will definitely renew the thread. I'm very curious weather our hardware upgrade in the future will free us of these problems.
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