Wolfgang, that's the technical way. There's a very simple way to get the average color of the sun. White is the reflection of all colors of the sun with the same reflection coefficient for each color. Hence the average 'color' of the sun is white. An ordinary light bulb has a color temperture of about 3200 Kelvins, and is a bit on the yellowish side. JennieG, use nothing but bright candles and you'll get your yellow world, less bright candles will give you a reddish one.