How to Get Rid of a Tumblr Background
- 1). Sign in to your Tumblr account.
- 2). Click the link to your Tumblr page on the right side of your dashboard.
- 3). Click "Customize" in the upper-right corner of your page.
- 4). Click "Theme."
- 5). Scroll through the list of themes to find one that you want and click on it. If you do not see one in the list, click "Browse More Themes." Scroll through the new list that appears, click on a theme that you want, and click "Install Theme."
- 6). Click "Save + Close" to confirm your background selection.
Source...