Questions on brightness of old colour TVs

I made a post about color reproduction a while back on this one TV I have. It is this 1972 Sears 8" portable color solid state set I have. It has a delta gun tube, and no black matrix. I made sure and double checked that I had proper greyscale and background setups. I try to set all my sets for 6500K for a neutral white. I used a split field NTSC EIA color bar pattern to adjust my color saturation and hue properly. I have the brightness and contrast adjusted correctly. What clearly stands out is the green is actually green and not yellowish. It is a very distinct difference that stands right out. And the red is actually red and not orangish. Blue looks about the same, but looks like it has more contrast in it. What I have noticed is the yellow reproduction is a bit weak. But overall, it looks very different and good.

This is the only TV so far I've seen look this way. Forgive me on this as this is the oldest color set I've used in my life so far. It is a Japanese make, and the picture tube # is 250TB22.