**System Information**
Operating system: Windows-10-10.0.22000-SP0 64 Bits
Graphics card: NVIDIA GeForce RTX 2080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 512.96
**Blender Version**
Broken: version: 3.3.0 Alpha, branch: master, commit date: 2022-06-05 19:05, hash: `rB8589f60546b3`
Worked: not sure
**Short description of error**
An object with 0 density volume but has an emission strength, will render out a broken image(what ever image format). The image file which is viewable inside blender image viewer turns out emtpy when opened with any other software.
{F13333574}
**Exact steps for others to reproduce the error**
Just download the attached blend file to test.{F13333586}
I came up with two solutions to get around this bug:
```
NO,1 just get some value for the volume density, while the result became UN-Denoisable; **Edit: it's denoiseable, just need more samples.**
NO,2 inside the compositor, feed the set alpha node with the image data itself as alpha, and switch the mode to "replace alpha"
```
Possible cause of the problem:
```
NO,1 obviously a object with only emission but with 0 density is ambiguous for blender to render which ends up with unexpected viewable content
No,2 the result should be encoded with straight alpha but not premultiplied.
```