A prop postcard of Arkham Sanitarium, based on a period painted-color example. To produce the finished prop, click through to download the high resolution version, download the back and postmark over here, and then:
1. Print the front image on cardstock and trim it to 4" X 6".
2. Adjust your printer document size to 4" by 6", flip over your trimmed card, and print the back side.
3. Apply stamp.
4. Run the back side of the card through the printer again to apply the postmark.
Optionally, you can follow that up with a rubdown with fine sandpaper along the corners and edges, then apply a light wash of tea to age the finished postcard.
Update: It escaped my age-addled memory that I had a new card back already finished. Just click through for the high resolution version.