As an Architect I used to draw like that. These are known as Blueline or Blackline prints. The originals would have been drawn on velum paper or even linen. Back when these were drawn they would have been printed as blueprints. The background would have been blue and the lines and text would have been white. Those drawings were probably printed in the 70's or later. Not that valuable. Original blueprints would be worth more. The original pen or pencil drawings would be worth the most. If it was a local landmark building such as a theater, courthouse or architecturally significant building you could probably sell them.
The street map is typical of the maps found in the courthouse records of each district. These are plot plans. An out line of the plots in each district. No real value unless the official records don't exist.
The house plan would be a keepsake for the owner of the home that was built from them. Not much of a market for them otherwise.
If you like them you could frame and display them but the paper will yellow quickly when exposed to light. The paper these are printed on is kept in the dark. The original drawing is placed on top and exposed to a bright light than an ammonia wash to remove the chemicals. Similar to printing a photograph.
Last edited by Hotfoot; Feb 19, '11 at 11:33 AM.
Too many toys. Not enough space!