All the above colors are in the neuter gender.  Most of the colors are adjectives. That means they have all three genders.
 So the color Μαύρο (black) can be: Μαύρος (Masculine) or
 Μαύρη (feminine).
    The colors Μπλε and  Ροζ don't have another gender except neuter.
    The color Καφέ (brown) in the masculine form ( Καφές ) means coffee.
    The color Πορτοκαλί it can be the fruit orange, if you change the accent. So το πορτοκάλι means orange ( the fruit)