I'm looking to take good pictures indoors when lights are on. I understand the kelvin would need to be around 2500 and AWB and the other settings can't get to this level.

So basically I want to set the CWB on my 20d.

I've got an idea of how to set this from the 20d manual but just have a question.

Is it best to take a picture of say the white wallpaper from the room I will be taking pictures from or is it best to take a picture of white / grey card?

If white / grey card would I take a shot of this in the lightened room or any time of the day?

I haven't taken a picture with the CWB so maybe there is a chance pictures will come out fine in lightened rooms with this setting

Thanks for any advice.