Ineffective bloom in render output when the background is transparent. #70403

New Issue

Hoffman Heard · 2019-09-30T22:22:52+02:00

Hoffman Heard commented

2019-09-30 22:22:52 +02:00

System Information
Operating system: win10 x64
Graphics card: Navidia GTX970M

Blender Version
Broken: Blender 2.80 and Blender 2.81-ff10ff782bde
Worked: (optional)

Short description of error
If I activate bloom in eevee and activate transparent background, the viewport will still show beautiful bloom, but If I render it, either render image or render animation, will output images in which bloom does not show at all.

Exact steps for others to reproduce the error
Based on the default startup or an attached .blend file (as simple as possible).
Add emission shader, Activate bloom, Activate transparent background, hit render.

Figure 1 is viewport, Figure 2 however is the final output. The blender file has also been attached.
BUG report.blend

**System Information** Operating system: win10 x64 Graphics card: Navidia GTX970M **Blender Version** Broken: Blender 2.80 and Blender 2.81-ff10ff782bde Worked: (optional) **Short description of error** If I activate bloom in eevee and activate transparent background, the viewport will still show beautiful bloom, but If I render it, either render image or render animation, will output images in which bloom does not show at all. **Exact steps for others to reproduce the error** Based on the default startup or an attached .blend file (as simple as possible). Add emission shader, Activate bloom, Activate transparent background, hit render. ![Demonstration.png](https://archive.blender.org/developer/F7782294/Demonstration.png) ![demonstra 2.png](https://archive.blender.org/developer/F7782296/demonstra_2.png) Figure 1 is viewport, Figure 2 however is the final output. The blender file has also been attached. [BUG report.blend](https://archive.blender.org/developer/F7782298/BUG_report.blend)

Hoffman Heard commented

2019-09-30 22:22:52 +02:00

Added subscriber: @HoffmanWood

Philipp Oeser commented

2019-10-02 13:21:38 +02:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2019-10-02 13:21:38 +02:00

Color is still there, it is just the Image Editor displaying it with the alpha applied
If you look at it in the Image Editor > Display Channels (top right corner dropdown) > Color (not Color And Alpha) you can still see the bloom in the image.
Also opening rendered images in an external Image Editor like Gimp and disabling the Alpha channel there displays the image correctly.
Dont think the postprocess bloom should be in the Alpha?

Color is still there, it is just the Image Editor displaying it with the alpha applied If you look at it in the `Image Editor` > `Display Channels` (top right corner dropdown) > `Color` (not `Color And Alpha`) you can still see the bloom in the image. Also opening rendered images in an external Image Editor like Gimp and disabling the Alpha channel there displays the image correctly. Dont think the postprocess bloom should be in the Alpha?

Philipp Oeser commented

2019-10-02 13:34:15 +02:00

See also discussion in
https://devtalk.blender.org/t/rendering-with-transparent-png-doesn-t-render-the-bloom-effects-eevee/3472/21
https://blenderartists.org/t/rendering-with-transparent-png-doesnt-render-the-bloom-effects/1126303

There have also been multiple reports about this
#65269
#67110, #67566, #66465, #66263

So in the end, this really seems to be the same as #52680 (Alpha difference Viewport/F12 ), will merge these reports...

See also discussion in https://devtalk.blender.org/t/rendering-with-transparent-png-doesn-t-render-the-bloom-effects-eevee/3472/21 https://blenderartists.org/t/rendering-with-transparent-png-doesnt-render-the-bloom-effects/1126303 There have also been multiple reports about this #65269 #67110, #67566, #66465, #66263 So in the end, this really seems to be the same as #52680 (Alpha difference Viewport/F12 ), will merge these reports...

Philipp Oeser commented

2019-10-02 13:34:34 +02:00

Closed as duplicate of #52680

Philipp Oeser closed this issue

2019-10-02 13:34:34 +02:00

Hoffman Heard commented

2019-10-02 13:46:32 +02:00

In #70403#787646, @lichtwerk wrote:
Color is still there, it is just the Image Editor displaying it with the alpha applied
If you look at it in the Image Editor > Display Channels (top right corner dropdown) > Color (not Color And Alpha) you can still see the bloom in the image.
Also opening rendered images in an external Image Editor like Gimp and disabling the Alpha channel there displays the image correctly.
Dont think the postprocess bloom should be in the Alpha?

Thanks for replying, your method works to show the bloom, although the problem is not only the image editor but the actual output as well.
Reading the discussion you posted, I see that bloom will disappear because of the way that blender handles alpha channel.
I wonder whether developers will try to change it in the future or just keep everything as it is now?
In the discussion I realize some people use composites node as a work around, In that case using other image/video editing tools seem more applicable than bloom in blender.

> In #70403#787646, @lichtwerk wrote: > Color is still there, it is just the Image Editor displaying it with the alpha applied > If you look at it in the `Image Editor` > `Display Channels` (top right corner dropdown) > `Color` (not `Color And Alpha`) you can still see the bloom in the image. > Also opening rendered images in an external Image Editor like Gimp and disabling the Alpha channel there displays the image correctly. > Dont think the postprocess bloom should be in the Alpha? Thanks for replying, your method works to show the bloom, although the problem is not only the image editor but the actual output as well. Reading the discussion you posted, I see that bloom will disappear because of the way that blender handles alpha channel. I wonder whether developers will try to change it in the future or just keep everything as it is now? In the discussion I realize some people use composites node as a work around, In that case using other image/video editing tools seem more applicable than bloom in blender.

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Ineffective bloom in render output when the background is transparent. #70403