What causes these artifacts in the sky

[mjcmt]

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.

Shot RAW converted to tiff so I could edit in silver efex.

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.

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.
View attachment 204491

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?

That's what I do.

 

[mjcmt]

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.

Shot RAW converted to tiff so I could edit in silver efex.

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.

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.
View attachment 204491

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?

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

 

[nokk]

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.

 

[mjcmt]

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.

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.

 

[smoke665]

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

 

[nokk]

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.

 

[mezcalpaloma]

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.

 

[Sharpshooterr]

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

 

[smoke665]

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