Header Hero section of Essence Pro has a dark gradient on top of the image so that text is readable.
If you are looking to remove this gradient possibly because you want to use your own “dark” background image simply edit /wp-content/themes/essence-pro/lib/header-functions.php
and change
$output = '<style type="text/css">.header-hero { background-image: linear-gradient(0deg, rgba(0,0,0,0.5) 50%, rgba(0,0,0,0.85) 100%), url(' . esc_url( $bg_image ) . '); }</style>';
to
$output = '<style type="text/css">.header-hero { background-image: url(' . esc_url( $bg_image ) . '); }</style>';