Parallax image problem in North theme.

Hello, I am new to web-development and i have started wordpress training from the very beginning. I want to get rid of background color as shown in Pic 1.
Pic 1:

i am using Siteorigin hero widget, so that i can uplaod HD image for parallax effect. Everything is going well except that black background color bar is appearing with image.. here are my settings

also the background color opacity is all the way to zero.

Kindly let me know, what i am doing wrong.
By the way i am using theme North.

Regards
Schahzaad