When the device powers up with the T Mobile screen, it's in color and then goes to a black and white or grey scale kind of scheme and nothing I do brings back the color. The wall paper screen with all the brushes and paints in black and grey is particularly impressive!
Fixed it. Go to "Settings", "Display", "Reader Mode" (That was the confusing part.) and then chose the "Blue Light Filter" level that you want (you can also choose "Black and White", which is where it was set.) "High", "Medium" and "Low" all yield a color screen.