There were no special coverings. What you see is just the painted ductwork. I am honestly not sure exactly what paint was used. It was applied with a sprayer.

I did this in our basement. Masked off the walls, covered the floor and everything I couldn't move out of the area, rented the sprayer and got to work. 600 square feet used 9 gallons of Glidden flat black paint (Home Depot has it in stock, no mixing needed). It took about 3 hours of spraying plus prep and cleaning the sprayer afterward for a total of about 6 hours. Had to stop and bag the lights each time I got to one of them so it was pretty dark toward the end. I held a shop light in one hand, the sprayer in the other, dragged a stool to stand on, and used a small foam roller to smooth out any drips as I went. It looks GREAT. Total cost was about $325 with the rental, paint, masking paper and tape.

Reminder: Spend the time to fasten / straighten / clean up all of your wiring and stuff in the ceiling before you start.

Hint: Wrap any water valves and cable connections in the ceiling with Saran Wrap before you paint. It's easy to remove after the paint has dried and no sticky connections.

Hint: Buy one of those Tyvek painter jumpsuits for $10 and wear it including the hood. I also wore booties over my shoes and a face mask so I didn't breathe in the overspray. I tried wearing goggles but that didn't work. When I was done all around my eyes and my hands were covered in paint but the rest of me was pretty clean.

Thanks for the run down. Glad it worked out.

Susan, thank you for the great instructions. One question: if you wrap all the cables, wires, etc in Saran Wrap - after the black paint has dried won't they be more obvious and stick out?

I believe that Susan was only saying that you wrap specific items in saran wrap to protect them from the paint (i.e. water shut-offs and connections points). You would take the saran wrap off after it dries.