Colour and brightness - what are they?

[austinarg]

I've recently heard this two words very often when talking about piano music, and I must confess I have NO IDEA of what they mean  . Could someone please elaborate?

[j_menz]

They are used as metaphors to describe the tonal qualities and emotional impact of music. Beyond that, I don't think there's a standard definition, though there will be a certain commonality of meaning.

Brightness, for example, could be used to describe both a certain light cheerfulness and a clear distinct tone.

[iliveinapiano]

What exactly is meant by tone? because I know for certain that the only things effecting the quality of notes are their volume, duration held and use of pedal. Oh, and the piano.

From what I've gathered colour is a very vague word often used to describe rich flowing harmonies played with sensitive dynamic control aimed at bringing out the harmony along with quality use of pedal also aimed at bringing out the harmony and the resonance of harmonic keys. Key changes are colourfull, progessive harmony is colourfull, so the way I see it, it is all about harmony.
Listen to Chopin prelude in csharp minor op.45 performed by Ashkenazy for example and you'll see what I'm talking about.

I don't really know what I'm saying or if it made any sense so I could be completely wrong.

J_menz is right about brightness. It is a quality of tone. You can have a warm tone or on the opposite end a bright tone. It could be the piano itself that is bright sounding (more high frequency harmonics with the sound of a note) or warm sounding (more low frequency harmonics). When it comes to creating a bright sound on a piano on would find simply that louder notes are brighter and softer notes are warmer. Playing a note more loudly simply sets more high frequency resonances in motion making it brighter.
But of course teachers like to complicate things and tell you to play with a 'warmer' tone instead of telling you to play more softly to create a warmer tone.