Blue ghost spots all over the screen Pan...

TV screen now has a blue film covering most of the screen. The people are shown twice, double figure with the second one in blue. The blue picture tube is working, but when I cover it up with a book, the blue spot are gone on the screen and picture looks normal expect the color is not
correct. Is this a bad blue picture tube? Can something else cause this? I have a part number for the picture tube, any other part number you recommend replacing before I do this. Thank You