You can use a header image for this purpose. Go to Appereance->Customize->Header Image. And regarding the none display of site title and description you can use blank value on the customizer option for site title and tagline.
I’m not understanding… I’ve attached a screen shot below.
With a full header image in place, when I enter a site title, it shows on top of my header image. I need to know how to give my site a title without it showing through my desired header image. I do not wish to use the logo function. I need this header to be customized. header.jpg