I use the compositor to save my renders into files with the "File Output" node. I want to have the smallest file size while preserving all information. I use PNG file format with the highest compression ratio, i.e. 100%.
My problem comes from the output file size. It seems that the compression ratio in the "File Output" node is not the same as the one when manually saving the image with the Image Editor (Image Editor > Image > Save As...).
Here are the figures with the default Cube rendering.
File Output node in compositor :
- PNG 0% : 8.3 MB
- PNG 15% : 1.0 MB
- PNG 100% : 610 KB
Manual saving via Image Editor :
- PNG 0% : 8.3 MB
- PNG 15% : 75 KB
- PNG 100% : 38 KB
So for the same level of compression, I have different image size.
Maybe I miss something. Can anyone help ? Thanks.
Blender version : official 2.82 on Linux.
Screenshot of my compositor node settings :
File browser with file sizes :
All files look the same (resized below) :