It could be the colour space you are working in. Try adjusting your colour settings within the PS3 settings. Unlike movies where they have tight regulations on what colour space they work with so that the directors intentions can be replicated in calibrated cinemas and homes alike, games do not have this regulation so making sure your TV/Monitor is set and calibrated correctly and the PS3 is outputting the correct colours then you should be removing the posibilty for colour errors at least from your end, then its upto other people to make sure they have a calibrated set.
For example, I run my PS3 and my iMac through the same Sony 46" LED - LCD TV. Both are outputting RGB and the TV has also been set to this colour space too, with various enhancing features turned off as they introduce problems. The white LED's in my TV can produce a very cold and Pink/Red image so the TV has been calibrated to the best of my ability to try and iron out as many colour and Gamma problems as I can.
This has resulted in my images from GT5 on the PS3 and the iMac to my eyes are the same without any deviation.
I will post my settings when I get home if this will be of any help?