Hi there –
There’s an opacity filter in place. It can be removed with CSS. Please share a link to your site. Knowing which version of WordPress you’re using will dictate how/where you add that CSS.
All you need to do is change the background color here.
body:not(.no-header-image) .custom-header-image:before, .lodestar-front-page .custom-header-image:before {
<strong>background: rgba(0,0,0,.5);</strong>
bottom: 0;
content: "";
left: 0;
position: absolute;
right: 0;
top: 0;
}