option to change passpartout color

Hi,

I know I made the request long time ago, but trying it again. would like to have the option to change the Passepartout color for viewport rendering.

Reason behind this is, that the Passepartout(background) effects how image is perceived.

For movies a black background should be fine, but when the final product is printed on the white paper, I need to check the images after rendering again with a white background if the colors a fine and make color/brightness adjustments.

Best regards Anders