Way to change background color of cell in Library grid view LR 6?

I know this is a year old post - but for anyone still looking for an answer this might help.... If you are just wanting to see the photos with a consistant background and not interested in all the date, you could simply use the "Lights Out" function (press L). You can set the "lights out" color to black, dark grey, medium grey, light grey and white. If you press L once it just become transparent so you can still see the data, flags etc, but it makes the background more coherent and I like to set it for white If you press L twice it's solid color.
Might be helpful

Try here: