A blouse that might be Bright Winter and a fur that could belong to True Summer. Imagine if the fur's white were your hair colour. It will appear to more drab and dull as the blouse gets brighter. The reverse: If the blouse is your hair and the fur is your blouse, it will look dingy. The broad stroke advice is Know Your White. Sounds good but it helps nobody specifically. To have your own key, you need your own colour palette from a colour analysis.