Interlaced images is what severely downgrades TV quality. Every frame that the TV set displays has only even or odd lines. It causes an slightly annoying effect. You'll notice it clearly in a monitor if you check an interlaced setup for your display.

About the images being dark I suppose it's the emulator's setup fault. Less colorful? Maybe it has to do with PAL format. What I can grant you is that us European get more horizontal lines than you Americans. Appart from contrails, did you see them? What do tou think of them?

The improvements can come from some filters that are applied to the images that require a 3D processing power that our old PSX doesn't have. And being wip3out high-res (I think it was 640x480) I think it's generating a bit more information than what the TV can really display (the real number of lines a PAL TV can display barely reaches 600 because some of the 625 said lines are used to let the electron beam go upwards when a frame is finished). However, 640x480 will always be better than 320x240. I'm sure a PSX game developper like Nick can talk more wisely about this than me, a mere amateur.

PRACTICE LEADS TO PERFECTION !