Photoshop: Gradient banding when zoomed out, clean when zoomed in

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  • Problem
  • Updated 6 months ago
  • (Edited)
Pic attached.

When an image is zoomed out beyond 66.6%, PS CC 2018 seems to use a lower colour depth, which is affecting my ability to work with very subtle colours.

I've also noticed this in the 2017 version. Not certain about before then.

Reproducible:
Hardware acceleration on/off
8bit/16bit
screen calibration on/off
Multiple files

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oggyb

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Posted 6 months ago

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Sam

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This is caching and it's normal, depends on the Performance > Cache Levels settings and probably size of the document and whether you're in 16 or 8bit..
It's usually some adjustment layers that show fully rendered only if you're above a certain zoom.
(Edited)
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Todd Shaner, Champion

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See this post for possible causes and some solutions:

https://forums.adobe.com/message/5174584#5174584
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oggyb

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Thanks for the replies. I've set cache to 1, disabled GPU, and checked my nVidia control panel. I've also restarted Ps between tests. No change I'm afraid.

I know my screen is calibrated with a white point of slightly cream-white, but this doesn't impact normal gradient smoothness, and the quality difference between on and off is negligible even in very fine colour areas.
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eartho

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Is your image in the ProPhoto color space?
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oggyb

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Nope, almost all my images are in Adobe 1998. The rest are sRGB.
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Todd Shaner, Champion

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Try updating PS CC 2018 to version 19.0.1 released today.

Does that fix the issue? If not what OS version, system model, display model, monitor calibrator and Luminance, Gamma, WP Color Temperature K settings are you using? Try changing the system display profile to sRGB if the display is standard gamut and Adobe RGB if wide gamut.
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oggyb

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I updated before commenting yesterday. I too thought it could be fixed by the update, but it wasn't.
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Rayek Elfin

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This is expected behaviour in Photoshop. When the 16bit mode in Photoshop was implemented, it was decided to "cap" the image pyramid of the viewport when displaying zoomed out 16bit images (threshold seems to be around the 67% before this behaviour kicks in). This means banding becomes quite obvious depending on the image. At the time it was probably done to optimize memory usage.


On a side note, it is also important to be aware that Photoshop's so-called "16bit" mode is actually 15bit, since it was easier to do calculations in 15bit, rather than 16bit. Unfortunately, this does result in capped full range 16bit HDR images (which, when opened in Photoshop, are capped to 15bit, and precious data is lost). Photoshop does not warn the user about this, so be cautious.

Both limitations of the 16bit mode have never been fixed/improved, and continue to bug people. In particular the banding's cause becomes quite confusing to most users. In the worst case scenario users start to process/degrade their 16bit images with noise and other de-banding techniques, while this is unnecessary and merely caused by the zooming out and the capped image pyramid.

No other 16-bit capable image editor on the market has this problem. It makes Photoshop's 16bit mode only partially usable for production work: if you are working in 3d, visual effects, and must process full-range HDRi, avoid Photoshop.

I hope the developers will fix this at some point. It's a bit of a ridiculous situation, of course.

Reference:
https://feedback.photoshop.com/photoshop_family/topics/bug-cache-level-setting-introduce-massive-ban...
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oggyb

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Wow, that guy Chris Cox really didn't get it.