
Hi Guest,
Would agree with the previous response that your girl is a little too young yet, far better to leave her at least one more season so she is 2 years old before she's mated. As you know, the Dane is a giant breed, and at 18 months she's not mature yet. Give it a little longer and ensure you have no problems.
Re. colour - it depends entirely on how the black boy is bred as to whether he's appropriate to mate to a harlie. If he is a black from harlequin breeding (i.e. only blacks and harlequins within 5 generations) that's great. However, he could be a black from black/blue breeding, which is not so good and will start introducing mismarks. He could also be a black from fawn or brindle lines, and that's not good at all!! - some very strange combinations possible from that.
So, you need to take the extra time and have more of a look into what's behind him. Hope that helps :D
Marina