There have been a number of features added in the PS3's 1.80 firmware update; many of which have been overlooked. The PS3 now supports Super-White and x.v.Color output, playing Blu-ray movies at 24Hz, and now an RGB Full Range option is enabled for those with HDTV's that support it. This latter option increases the range of colours in PS3 playback, making both films and movies have a much wider range of colour. Continue to see the results for when RGB Full Range is enabled, and how to see if your TV supports it.
If [Full] is set when using a TV that supports RGB full range (only over HDMI), the picture quality of the game or video may be improved, increasing the colour spectrum from 16 to 235, to 0 to 255. Not all HDTV's will support this, however, but if your television does then blacks will look blacker than ever and see some details which may have been missing before.
Here is a comparison picture to show the difference (please ignore the lines on the second image, this is not a result of RGB Full). Roll over the Uncharted: Drake's Fortune image to see the results of RGB Full (credit to PSN: Violater):
Thus, the results are noticable and can bring a new colour depth to your experiences with the PS3. However, it is not optimal for all televisions and can distort colours. This means you will have to experiment with your HDTV's brightness and contrast settings. Nonetheless, how can you discover whether your HDTV supports this new RGB Full option?
Here is a test to find out (credit goes to andrewfree of neogaf):
First, save this image, and put it on your PS3 via a memory card or some other method:http://sr-388.net/images/patterns/Brightness.jpg
With the option set to limited, adjust the brightness control on your TV until you can see most/all of the boxes. There are 12 boxes there, but you might not be able to see them all. You should hopefully be able to see at least 9/10 of them.
Now switch it over to Full range. Can you still see all the boxes? It's very likely that you will only see a full black screen now if you're using a HDTV rather than a DVI monitor.
If you can turn up the brightness control and see the same number of boxes again, then it seems your display does support the full range. If it stays black, or you can't see as many boxes as before, your TV does not support the full range option and you should be using limited.
So try it out, but it should noted that most HDTV's should have RGB set to limited.