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"Banding" in sky in Monochrom 246 images


Peter_S

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Hi!
I revisited some Monochrome images and saw some strange sort of banding in the skies. I tried to get rid of them, no luck. What could be causing this? The filter (B&W yellow as I remember)? The RAW converter is C1 Pro 10. It could be simply the monitor, but it shows on both my MacBook Pro and Eizo CS240 screen.

Best,
Peter
 

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Edited by Peter_S
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Looks like common JPEG artifacts. Pure monochrome images are even more prone to these than RGB images. Did you shoot in JPEG, DNG, or DNG+JPEG format?

 

By the way, the yellow filter might indeed add to the effect but only indirectly so. It darkens the blue sky, and darker areas are more prone to banding artifacts than brighter ones.

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Hi! I shot in RAW. The problem also shows when looking at the RAW on screen. Just looked at them in Iridium. Same thing. The banding creeps in whenever the photo is taken against the sun.
 

Looks like common JPEG artifacts. Pure monochrome images are even more prone to these than RGB images. Did you shoot in JPEG, DNG, or DNG+JPEG format?

 

By the way, the yellow filter might indeed add to the effect but only indirectly so. It darkens the blue sky, and darker areas are more prone to banding artifacts than brighter ones.

Edited by Peter_S
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Possibly overuse of the clarity slider (I suppose there is one in C1) Monochrom files are very sensitive to manipulating the midtones.  Or did you have to pull up exposure? Could you supply a DNG?

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I doubt it, as even the RAW without any manipulation shows it faintly and I am usually not so keen on the clarity slider. I will provide a DNG for a brief period to download: https://www.dropbox.com/s/vgvfplwe19opvni/L1001512.DNG?dl=0

 

Possibly overuse of the clarity slider (I suppose there is one in C1) Monochrom files are very sensitive to manipulating the midtones.  Or did you have to pull up exposure? Could you supply a DNG?

Edited by Peter_S
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pushed it here and there...finally saw banding on the top right..there is some weird grainy noise there and the banding is visible at certain settings in that area

 

Sensor seems Dirty too

 

Capture one PRO 11

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Irregardless of the cause ... should be able to ameliorate it with a small amount of grain. Which could be added to the sky in a layer.

 

A wonderful shot it trying conditions. 

 

Bob

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Converted in Photoshop CC. Let's compare...

 

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I saw very little banding but processed the dng and added a bit of grain ... 

 

 

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Lens profile corrections in LR used to be a source of banding. I am

Not sure if they exist in C1 or if the problem still occurs with Adobe

products. My Monochroms have been gone for quite a while.

 

I find that the longer I work with a picture ... months ... I am likely

to find a preferred interpretation that is different from my original.

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Hi all! Thank you so much for your help and working on the file! I appreciate it. I worked around on the files now a bit and found that only LR (and I guess PS) avoids this banding - interestingly, it seems that opening it in Silver Efex brings the banding back - more notable on the Eizo; also the same tiff shows more banding in C1 than LR. Or maybe its just my eyes.
In Capture One I need to keep the sky relatively bright to avoid it. Any film preset applied in C1 amplifies the phenomenon. Interesting observations.


 

Edited by Peter_S
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Just as a reminder - ALL digital images are quantized (tonal gradients are broken up into discrete steps) and not "continuous tone" (infinite number of gray steps). With enough adjustments to tonalities (sliders: exposure, blacks, contrast, shadows, highlights, curves, etc. etc.) those steps can be separated enough to produce visible bands.

 

The Monochrom II actually delivers about 12-bit-data, or 4096 "steps" from black to white. Maybe less.... (Full 16-bit data would discriminate 64000+ grays).

 

https://www.l-camera-forum.com/topic/244450-monochrom-m246-dng-technical-analysis/

 

Easily enough to look smooth if left alone, and with quite a lot of headroom over 8-bit (256 "grays") - but not room for an infinite amount of tonal distortion in post-processing. You want "black skies?" - then you need a red filter, rather than yellow filter plus a lot of post-processing and "stretching" of the data to darken the skies more.

 

And once you convert to 8-bit - whether during the processing, or by converting to jpg - you lose even that headroom.

 

NB: to get more apparent grays out of a limited bit-depth, dithering is used to mix together different discrete tones in side-by-side pixels for better blending of the steps (smoothing the average difference between the bands or posterizing so that they are less obvious).

 

Heck, you can even get "grays" out of nothing but black and white pixels - with dithering. But there is a limit, at which point the bands or posterizing reappear: http://webstyleguide.com/wsg2/graphics/dither.html

 

You might check the user preferences or options of C1 to see if it has settings to control if and how the dithering is done (there are several different algorithms to dither data). Adobe may just have better algorithms (or better default algorithms).

Edited by adan
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Adan, I was actually just thinking along these line, you clarified it - thanks, makes sense!
 

Just as a reminder - ALL digital images are quantized (tonal gradients are broken up into discrete steps) and not "continuous tone" (infinite number of gray steps). With enough adjustments to tonalities (sliders: exposure, blacks, contrast, shadows, highlights, curves, etc. etc.) those steps can be separated enough to produce visible bands.

 

The Monochrom II actually delivers about 12-bit-data, or 4096 "steps" from black to white. Maybe less....

 

https://www.l-camera-forum.com/topic/244450-monochrom-m246-dng-technical-analysis/

 

Easily enough to look smooth if left alone, and with quite a lot of headroom over 8-bit (256 "grays") - but not room for an infinite amount of tonal distortion in post-processing. You want "black skies?" - then you need a red filter, rather than yellow filter plus a lot of post-processing and "stretching" of the data to darken the skies more.

 

And once you convert to 8-bit - whether during the processing, or by converting to jpg - you lose even that headroom.

 

NB: to get more apparent grays out of a limited bit-depth, dithering is used to mix together different discrete tones in side-by-side pixels for better blending of the steps (smoothing the average differnece between the bands or posterizing so that they are less obvious).

 

Heck, you can even get "grays" out of nothing but black and white pixels - with dithering. but there is alimit, at which point the bands or posterizing reappear: http://webstyleguide.com/wsg2/graphics/dither.html

 

You might check the user preferences or options of C1 to see if it has settings to control if and how the dithering is done (there are several different algorithms to dither data). Adobe may just have better algorithms (or better default algorithms).

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