# What causes these artifacts in the sky



## mjcmt (Mar 14, 2021)

What causes these rings in the sky? I finally got around to doing a b/w where it's most noticeable. Is it the lens?
Shot w/ noise Canon G-10 Powershot compact camera.




Carolina Beach, NC 2009


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## 480sparky (Mar 14, 2021)

Banding.  Caused by post-processing.


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## smoke665 (Mar 14, 2021)

What he said^^^^. Here's a little reference on it Identifying and Repairing Banding - Digital Photo Magazine.


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## nokk (Mar 14, 2021)

as stated above, it's banding.  it's likely due to the histogram being stretched too far in editing.

however, one of my computers has an issue where banding shows up on about half of my images.  it's not just the monitor, the banding is still on the image when viewed on another computer.  the same file, processed the exact same way on a more powerful computer will not have any banding.  so if you're not doing much to the file it may be the computer.


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## mjcmt (Mar 14, 2021)

Ok I edited from a tiff 16bit file. I tried another that is slightly different w/ less sky. Still banding in sky. Maybe its the computer like Nokk suggests.


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## 480sparky (Mar 14, 2021)

It also might be the quality setting you're saving the file at.  100% is best, and maybe you're saving the file at 80% quality.


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## smoke665 (Mar 14, 2021)

Something else you might look at

Are you editing in Lr, Ps, or both? 

Metadata shows processing Google Silver Efex Pro. I'm not a big fan of it, is the banding there before you used Efex?

Metadata shows: *WARNING:* Color space tagged as sRGB, without an embedded color profile. *Windows and Mac browsers and apps treat the colors randomly*. which could be a problem.
Finally did you use any adjustment brushes or gradient filters on the sky?


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## greybeard (Mar 14, 2021)

I get that kind of banding when I export to jpg in LR and I set the quality slider too low.


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## Space Face (Mar 15, 2021)

As stated most likely PP compression.  Over sharpening,  excessive NR and file size changes are the most common caused I find.  Difficult to get rid of other than starting from scratch.


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## JBPhotog (Mar 15, 2021)

mjcmt said:


> Ok I edited from a tiff 16bit file. I tried another that is slightly different w/ less sky. Still banding in sky. Maybe its the computer like Nokk suggests.
> 
> View attachment 204445



Which capture format did you shoot in Raw or JPEG?

Your G10 can shoot in Raw but if it was shot in JPEG the compression in camera could have tossed out usable information. It doesn't matter if you import a JPEG then convert it to 16 bit for additional processing, you don't gain information lost during the in camera post processing.


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## mjcmt (Mar 15, 2021)

JBPhotog said:


> mjcmt said:
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> > Ok I edited from a tiff 16bit file. I tried another that is slightly different w/ less sky. Still banding in sky. Maybe its the computer like Nokk suggests.
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Shot RAW converted to tiff so I could edit in silver efex.


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## nokk (Mar 15, 2021)

mjcmt said:


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if you have lightroom try using the edit in feature.  it'll do the same thing as converting to tiff and opening in silver efex, but presumably with the best export options.  do the artifacts appear before or after you edit in silver efex?  if i had to take a guess i'd say it's the editing process and not the computer.


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## mjcmt (Mar 15, 2021)

nokk said:


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I don't have light room. I use Apple's free Photo editing program on my iMac. It's only an occasional photo. This photo taken at the same time doesn't have banding.


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## nokk (Mar 15, 2021)

mjcmt said:


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it's pointed in a different direction which means you'll have different tones in the sky.  this image is shooting with the sun at your back so the tones in the sky have less variation.  the other shot is almost into the sun, so there's a lot of tonal variation in the sky (brighter towards the sun, darker further away).  if the histogram compressed and stretched while editing the image then you're going to have banding where the different tones break apart.

when in the editing process does the banding appear?  is it when you first open the raw file?  after the tiff conversion?  after silver efex?


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## JBPhotog (Mar 15, 2021)

mjcmt said:


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Which "free" editing program are you talking about?
If it is the Photos App make sure you are selecting the "Export" and select the dropdown next to Tiff and check the box next to "16 Bit" otherwise it will export an 8 bit Tiff. Then choose "AdobeRGB" for the colour profile.

Is there a reason you aren't using Canon's DPP software to convert your Raw files?


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## mjcmt (Mar 15, 2021)

JBPhotog said:


> mjcmt said:
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That's what I do.


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## mjcmt (Mar 15, 2021)

nokk said:


> mjcmt said:
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It appears when I lower the brightness slider in silver efex to tone down the sky.


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## nokk (Mar 15, 2021)

mjcmt said:


> It appears when I lower the brightness slider in silver efex to tone down the sky.



there's your culprit.  look into darktable (raw editor) and gimp.  they're both free.  i wouldn't do anything other than the actual b&w conversion in silver efex.  to darken an image i'd use a more capable editor.


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## mjcmt (Mar 16, 2021)

nokk said:


> mjcmt said:
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> > It appears when I lower the brightness slider in silver efex to tone down the sky.
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Thanks. I have gimp and the latest update made it's operation jerky and jumpy, so I haven't been using it. I'll look into Darktable.


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## smoke665 (Mar 16, 2021)

mjcmt said:


> It appears when I lower the brightness slider in silver efex to tone down the sky



There you go. Remember back at the start I said _"Metadata shows processing Google Silver Efex Pro. I'm not a big fan of it, is the banding there before you used Efex?_" I pitched the Nik collection a long time ago because of issues.

Rather than messing with Gimp or Darktable, which offer little support, might I suggest Affinity. I don't use it, but there are several on TPF that do, and seem to be pleased with it. Right now it's on sale for $24.95 Affinity Photo – Professional Image Editing Software


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## nokk (Mar 16, 2021)

smoke665 said:


> I pitched the Nik collection a long time ago because of issues.



i still use it, but you're absolutely right about issues.  i use color efex pro sparingly and don't brighten or darken anything or otherwise mess with the histogram in nik, if i can help it.


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## mezcalpaloma (Mar 17, 2021)

Very nice image!

My guess is you're trying to pull too much tonal variation out of too little variation in the data. 

Assuming I'm right, here's the (cocktail napkin version of the) problem: Originally, the tones were very close together, so their digital numeric representations were quite close in value. When you then try to stretch them out, the tonal values are scaled (the computer doesn't "know" this is supposed to be a smooth gradient, so it doesn't interpolate). This _scales their difference_, producing a noticeable gap in the two tonal values. Since in a smooth gradient this change occurs along a line (an "isoquant", if you will), the boundary is obvious to our visual system as an abrupt step. 

I often use two solutions to this: one is to introduce "grain". This randomizes the transition point and destroys the organization of the isoquant or "line" where the transition occurs, hiding the problem. The success of this approach depends on the size of the step and the amount of grain you will tolerate. I don't use LR (I'm a PS type). In PS, go to Filters->Camera Raw Filter...->Effects and dial up Grain, Size and Roughness until you don't see it anymore. I'll let you research the effects of the three inputs...mostly cuz I don't know off the top of my head.

My other solution is to borrow from the architectural photographer's toolbox and composite in a sky. As long as you get a reasonable match in the lighting direction, this works quite well. 

Whether this helps or not, I hope that you find a solution.


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## Sharpshooterr (Mar 18, 2021)

Wow, Sparky and Smoke come up with some really crazy stuff!?
It's obviously a giant spaceship sitting just over the water with it's cloaking device on but the devices batteries are getting a bit low thus you can start to see it!!!
SS


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## smoke665 (Mar 18, 2021)

Gee @480sparky at least we aren't wearing tinfoil hats and seeing little green men!!!!!!


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