I think I have the answer to this one. Its the reason I chose the KLOV name that I did. My mom used to work for the Phillips tv company when they had a factory in my home town. The best models of their TVs used a black matrix tube. If I am not mistaken a TV is like a flourescnet light bulb. Ever bust a marquee bulb. They have a white coating. I think that is phosphur. The inside of the tube has a layer of phosphur as well. When the color guns hit the front of the tube, that spot glows for a short moment. But behind the phosphur coated glas is another part of the tube. Their is a metal matrix that resembles a very fine sieve or grating. I believe that was what makes the various tiny dots as the color guns scan across that matrix and eventually make up the picture(about 60 pictures a second). Most tubes have a matix that is grey. I have also seen green, white, and even brown once or twice. But the best tubes had black. I think they all did the same job in function, but black allowed for a better contrast ratio in the picture (like the black inking in a comic book to make the colors pop) The black matrix also blocks out more ambient light. Now, when you go buy an LCD flatscreen TV, you can actually shop for a unit with a higher contrast ratio which is why the best LCDs are dark flat black. I think the phosphor in a tube is white(or grey) in color, but a monitor that keeps repeating the same picture over and over will burn and fade the phosphor on the inside. Thats why the mazes on old pac man monitors are dark. All the phosphor has has been burned off and all that is left is the naked tinted glass. Of course, this is just what I have been told over the years and what I have picked up from tech friends. I could be way off.