PLUGE = Picture Line Up Generation Equipment. Really. I don't make this stuff up.
NTSC charts vary widely on the net. None are perfect. This one should be closer than most.
The colors are at 75%. You'll fry NTSC if you go higher. NTSC black does not look black on my new LCD display, and that's because it is not all the way down at zero. A true zero is in the black directly behind the EBEN letters. The Pluge is black +/- 4. On a TV set, the two left bars in the Pluge would look the same, and the one on the right would be just visible. This is how you set the black level on a TV. The reference white square on the bottom is 100%, and on a computer screen it should look considerably brighter than the "white" bar at left. If not, you need to back off the white level.