What color should I paint an Extra door on old duplex?

I would paint it as close to one of the neutral colors of the brick. If you feel confident enough try using several of the colors of the brick so the door and trim fade into . Good luck!

I agree with Heidi.

In fact, I would buy sponges & cut each into the exact size as the brick. Be sure to do one sponge for each different color brick. Then, get a quart of each color matching the brick. Using the concrete "grout" color, I would paint the door itself, the threshold AND ALL the blue trim around the door with that gray. Be sure to let thoroughly dry.

Don't be intimidated since it's a no brainer: you are sitting next to the wall, that is exactly what you want to paint on the door and surround. Follow the pattern.

Get little plates from Goodwill for a buck apiece and use as a palette for each color. These stand up better than paper plates which I have had blow away. Load the sponges with paint; pull some off by stamping on a newspaper. As I mentioned before, just use that exact "ramdon" pattern as the brick wall, start from the threshold and press the sponge onto the threshold, door trim: the casing, door jam and the stop as well as the door. Continue until done. Now, there should be no blue or beige showing on that door area.

You might need to touch it up a bit in spots but you will be comparing your color to the wall as you work and you will quickly figure how hard to push it onto the surface and how much paint to use. Now that the color is on, you will see that painting the surface with gray before starting was clever. You actually pre-grouted with the "concrete." Give it a day or so to completely dry and put two coats of an exterior, non-yellowing, flat polyurethane. This will protect your hard work!

Stand back and enjoy your work. Now, wasn't there an extra door around here somewhere??

Post a picture, please, when you are done.