It depends.
You wrote "colour", not "color", so I'm guessing PAL. And PAL is 4:2:0, not the nasty 4:1:1 you'd get with NTSC. With NTSC, 4:1:1 > 4:2:2 (or even 4:4:4) pre-filtering can be needed. But for PAL, eh. You can't recover lost colors, but the goal here is to widen the palette to prevent further loss, allow more nuance in correction.
Normally you'd just correct the DV in
VirtualDub directly (ColorMill), then save to lossless.
Avisynth and ColorYUV can help be helpful as a pre-correction, pre-
VirtualDub. Only sometimes, not even most of the time.
Code:
ColorYUV(autogain=true, autowhite=true)
BTW, I recently saw something in johnmeyer's film script, where he limits black/white values, and that'd be something to look into when doing these auto settings. I need to figure out how those work.