While looking through my records for something else I stumbled across this tidbit I'd forgotten I had scanned in:
I have a connection to Fort Casey; having spent time there as a kid (Fort Flagler as well for that matter). It's a single-piece scan, so there's not a lot I can do with it. But, while preparing it to post I figured I'd cover the steps I used, since I do post blue-prints on a regular basis. I could just post them in all their blue glory, but I know people like to print things, and I'd hate to be the reason a few printer ink cartridges choked and died, so I always make them black and white for better printing.
The process is below, and is based on the ancient Photoshop (6) I use. Invert the image, set a white point to make most of the remaining background color go away, then grayscale and level the file to darken the dark and whiten the white and remove the noise.
Takes no more than 30 seconds once you know how to do it; the harder part is cleaning up the borders and holes.
You can read more about these guns here (and you might even see a familiar drawing!):
They were a great place to run around in as a kit!