How to turn brightness back on from a black screen

Have an Samsung Tab 4 that I'm trying to increase the brightness on. When I went to the brightness slider, I turned it all the way down just to be sure that the slider was working...but something happened before I could turn the brightness back up....if I remember correctly, I tapped the brightness symbol and it went dark automatically....now I've got a tablet that turns on but only has a black image. How am I supposed to turn the brightness slider back up if I cant even see it? Is their another way to accomplish this?