.jumbotron
  .container
    .row
      .col-lg-12
        h1 Here is some text
.jumbotron
  .container
    .row
      .col-lg-12
        h1.second Here is some text

.jumbotron {
  background: url(https://images.freecreatives.com/wp-content/uploads/2017/06/628ab854fce7f90c30e40c91fb86b22b.jpg);
 background-size: cover;
}

h1 {
  font-size: 4em; 
  background-color: black; 
  padding: 1em;
  color: white;
  mix-blend-mode: multiply;
  display: inline-block;
}

h1.second {
  font-size: 4em; 
  background-color: white; 
  padding: 1em;
  color: black;
  mix-blend-mode: screen;
  display: inline-block;
}