Well, here are three photos from the U. of Arkansas:
but the spots appear, on my monitor at least, to be brown. My roses clearly haven't read the book
and insist on displaying much darker spots. My search phrase was
"black spot" roses photo
so you can find other diagnostic photos and, perhaps, find an exact match for your roses. (No digital camera in this house, so I have to "reverse engineer" a lot of stuff--like these rose photos, for example!