Blur background with Sharpen/Blur node

[dgruwier]

The Sharpen/Blur node seems to only affect rendered pixels and leave the background intact. Is there a way to make it affect the background as well, like how exposure and other color correction affects the entire frame buffer?
That would be useful in VFX when working with plates, for checking the overall lighting levels and colors in areas with lots of detail.

[viktor_angelov]

Hello dgruwier

Thank you for your feedback.

Could you please give us more information on how would this change affect positively your work?

[dgruwier]

Most of my job when doing VFX work is matching colors and light levels to an existing background plate. Blurring the image is akin to doing a squint test in painting, it gets rid of all the high frequency detail and texture that might confuse things, and leaves just the average colors across the image.

For example, lets say you have a real prop on set that has a lot of high frequency, high contrast texture or shapes. You recreate the prop in 3D, then load it into a shot to match the lighting to the original reference prop. But because of all the texture, it's difficult to tell if the color temperature, direction, etc. match perfectly, because it's just a lot of black and white shapes.
Blurring the image smoothes the details out, and makes it very easy to compare, color pick and examine the overall light intensity, color, direction, etc.


It's a small thing, not actually very critical to the workflow. I just feel tempted every time I see the blur filter to make use of it, and as it is now, I'm not sure why I'd ever want to. Besides, I'd argue that it's also the expected behavior. All other adjustments affect the entire image, background included, as far as I can tell.

[viktor_angelov]

Thank you for letting me know, dgruwier

We will discuss this internally and will contact you if it is further developed.