Japan ran NTSC without the black pedestal, and a set from the wrong country shows it... In American NTSC, black is not the darkest thing the signal can carry. The picture sits on a pedestal 7.5 IRE units above the blanking level, so there is a small step between "no picture" and "black picture". The margin existed for the receivers of the day: it kept genuine black clear of the blanking and sync region, where a set's clamping circuits live. Japan used the same 525-line system and skipped the pedestal. ITU-R BT.470, listing the difference between black level and blanking level for System M, notes that in Japan a value of zero is used. Black and blanking are the same level there, as they are in the European systems. That sounds like a detail until you feed one country's signal to the other country's set, because a receiver does not measure where black is. It subtracts the setup it expects. Send an American signal to a Japanese set and the set treats blanking as black, so the signal's 7.5 IRE pedestal arrives as dark grey and every shadow in the picture is lifted. Send a Japanese signal to an American set and the set removes a pedestal that was never there, pushing the darkest parts of the picture below black, where they clip together. The three panels here are the same night frame through the same chain of the AnalogTV app, with only the set changed. Measured on the darkest quarter of each picture, the matched pair sits at 34, the American signal on the Japanese set at 44, and the Japanese signal on the American set at 25, on a scale where white is 255. The middle one is the milky look of a picture whose blacks never reach black; in the last one the darkest parts of the picture start to clip together at black.