Dear Robert, one of our associates advises the following:

"It isn't possible to achieve a 485 red shade match that is opaque enough to cover the black background.

It will be quite a pastel looking match to contain sufficient white.

You could put a white down first then overprint a bright 485 match, but this depends if the job and the printer could register the overprint well enough."

Please let know how you get on, or if you have another question about this, please feel free to post again.