Hdr pro banding problem

[gabriele_1508]

Hi,

I'm using Photoshop 26 and camera Raw 17. Starting from 7 shots with bracketing -1.0 to +1.0 stops I have a banding problem merging with HDR Pro default setup (16 bit).

The area close to the sun has a lot of artifacts as show in the attach. I don't know why.  Could you help me to solve the problem? Thanks.

[D Fosse · Accepted solution]

Generally, with 16 bit data, any banding you see on screen is in your display system - which only has 8 bit depth.

Does the banding change when you change the tone mapping of the HDR file? If it does, the logical conclusion would normally be that it's in the display pipeline. However! - that assumes you have caught the full dynamic range of the scene with bracketing, which I honestly doubt with only a two stop range. This is an extremely high contrast scene, and I would assume five or six stops would be needed here, possibly more.

With a 32 bit file, what you see on screen is just a "window" into the HDR data. That's why you do tone mapping, to decide what part of the HDR data to fit into that SDR window.

[gabriele_1508]

Hi,

thanks for the quick reply. So, I need to use a 16 bit depth monitor to solve the problem, right?

What can I do at the moment to partially mitigate the problem?

[gabriele_1508]

Sorry, I covered -3.0, + 3.0 stop range, with 7 shots

[D Fosse]

There's no such thing as a 16 bit monitor, but there are some (expensive) 10 bit models that don't give you any on-screen banding if there isn't any in the file.

But the whole point of that was that if it's only in the display path, there's no real "problem" as such with the file itself. It can be perfectly fine. But that illustrates why a 10 bit monitor can be worth the extra cost - you know that what you see is what there is.

Take a look at your darkest exposure - the one that should contain all the highlights. If you change the exposure a bit in ACR/Lightroom, does it look like there's any channel clipping there? Is either the red or green channel burned out to solid white, or is there data all the way to the top? That's what would cause this type of banding.

[gabriele_1508]

There's no such thing as a 16 bit monitor, but there are some (expensive) 10 bit models that don't give you any on-screen banding if there isn't any in the file.

But the whole point of that was that if it's only in the display path, there's no real "problem" as such with the file itself. It can be perfectly fine. But that illustrates why a 10 bit monitor can be worth the extra cost - you know that what you see is what there is.

Take a look at your darkest exposure - the one that should contain all the highlights. If you change the exposure a bit in ACR/Lightroom, does it look like there's any channel clipping there? Is either the red or green channel burned out to solid white, or is there data all the way to the top? That's what would cause this type of banding.

By @D Fosse

Of course, but it is quite difficult to elaborate in such condition.

I think it's happening what you describe about red channel. In attach.