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So I'm using this physicall starlight & atmosphere addon, a wonderful addon, but it requires to change blender's addon to -6 to look good.

enter image description here

I'm working on VFX industry, so i need to renderout OpenEXR and ACES colorspace, (ACES isn't the problem here, i've checked using sRGB, same problem)

after making a beautiful scene with the addon, then leaving it to render overnight, then boom everything is overexposed. I've done some research, and somehow blender's OpenEXR Output doesnt read the exposure we do.

Viewport with -6 exposure: (how it should look) enter image description here

Rendered image: enter image description here

it literally looks like the file output ignores the -6 exposure, and just renders with 0 exposure

so, I'm trying to renderout OpenEXR file with exposure changes affecting the final render

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    $\begingroup$ Filmic is designed for much larger values.. With filmic (I don't use the built in version, I use the github repo) I find it works best to keep exposure at 0 and manage color and exposure with CDL node in compositor. There are many posts here about working with filmic and color management thereof. Start here and here maybe it helps... $\endgroup$
    – Timaroberts ♦
    Mar 6, 2021 at 20:32
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    $\begingroup$ The color management settings will be ignored when saving to OpenEXR, I guess you would have to use your compositor of choice. $\endgroup$
    – brockmann
    Mar 6, 2021 at 20:40
  • $\begingroup$ if i do the exposure change AFTER the render while the image is already blown out like that, there's no chance of recovering the lost detail in the exposure, :/ $\endgroup$
    – Fernaldy Wiranata
    Mar 7, 2021 at 6:16

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So it seems I got fooled by the "viewed" image, enter image description here I think it's blown up ,and unusable image

but after I put the EXR Image to Davinci Resolve, all the information is still there, the image is not exposed correctly ofcourse, but the information is still there, we will need extra effort to re-expose the image.

Before exposure fixing: enter image description here

After exposure fixing: enter image description here

so the conclusion is, while the view is super blown out, if we render in OpenEXR 16bit or 32bit, the information is still there and we can just pull and correct the exposure using the "hidden" image information

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By default only renders are displayed and saved with the render view transformations applied. These are the Render Result and Viewer image data-blocks, and the files saved directly to a drive with the Render Animation operator.

However, when loading a render saved to an intermediate OpenEXR file, Blender cannot detect automatically that this is a render (it could be e.g. an image texture or displacement map).

In your case - High Strength value ... enter image description here

... compensated by Color Management > Exposure is displayed, but not saved in OpenEXR file.

enter image description here

OpenEXR as intermediate format stores all rendered data without modifications (clipping range, color transformations, etc.) When opened in compositor you have to specify Exposure, Gamma, Color Space (LUT) again.

It can be done via Render Properties > Color Management or from 2.91 (I guess) also inside Compositing Editor with Exposure node. Don't use both at the same time since it would be doubled.

enter image description here

For more info see Blender Manual

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