Color of Yosemite Starup Screen

Ok, this is a weird question but why is the Yosemite startup screen white on gray on my 2012 MacBook Pro but it is white on black on my 2013 iMac? Are startup screen colors determine by hardware? Both machines are running Yosemite 10.10.1 with no current problems. The color difference has been there since the original public Yosemite beta.

I really don't know. It's the same on my 27" 2013 iMac as it is on yours. Maybe it has to do with screen brightness and contrast?

Hmmm. Mine starts out black on gray, turns to a kind of beige-ish backround.... and has always had this 'secondary start-up' where the progression goes from a single line to one 'framed' in a black box. Been wondering why at first the progress bar stops about halfway, changes appearance and continues...