Hi Vince, It's quite difficult to make a suggestion because I don't know the context you're using the typeface in - are you typesetting a book, magazine or what exactly?... my gut reaction would be to avoid pairing it with the serifs you mentioned, especially Castellar with it's 'engraved' appearance - because it looks visually very similar and would fight with your blackletter. I'd be tempted to look at pairing it with a sans-serif such as Akzidenz Grotesk, because of the immediate visual difference between the two.

It might be a good idea not to overthink this and just see what works on paper - print out different sample pages so you can compare them - pinned up next to each other on the wall, table or whatever. Try a sans like I suggested. Try various serifs - I think when you see everything together on paper, you'll be able to see at a glance what works and what doesn't - and so will your boss.

I'm afraid I've never used blackletter faces on any of my own projects, so I can't recommend a pairing straight off, I'm afraid; I don't actually mind the blackletter typeface, I've had my opinion changed many times when I've seen a typeface that I personally didn't like used really well!

Hope this helps.

Si

So do I.
To combine the "Gothic" font with Trajan would kill the "Gothic", 'cause the Trajan is too strong. I'ld use a Grotesk like Akzidenz-Grotesk or Helvetica. Its neutral and it lets the "Gothic" do its job.

Georg

Or possibly something geometric like Avenir.
http://www.myfonts.com/fonts/linotype/avenir/

Tim