Warm colors (yellow/orange/red) - good guys - Itachi, Obito/Kakashi - remember Karin's comment about Naruto's chakra being bright and warm?
Cool color (blue) - bad guys - Madara
Purple (mix of red and blue) - neutral - Sasuke
I don't think we know enough about Izuna to determine.
Cool color (blue) - bad guys - Madara
Purple (mix of red and blue) - neutral - Sasuke
I don't think we know enough about Izuna to determine.