I was curious about that too, I was recently working on a friend's car where the upholstery was replaced about 20 yrs ago. When it was new, it was bright white with just a hint of that pearl appearance. Now that the interior is older, the white has darkened slightly and that pearl like sheen is very apparent and kind of odd looking. My green turd project has a white interior, so I'll be purchasing new upholstery at some time. The door panels, also new at the time, don't have a pearl appearance at all...