Blueprints are not stable and will fade over time. They fade faster when exposed to light. There are companies that claim to restore, but IMO, they simply create a photograph of the blueprint and say that is the restored print.
That is unfortunate.
I should specify, though. While I do have an actual blueprint from the hospital campus, I also have a handful of "building plans" (not sure what they are actually called) - something similar to this:
Do you know anything about preserving this style? I don't know if this is printed on a special paper or if it's the same as an old movie poster.
