On April 15, 2018 at 21:49, Fins said...
Well, she got the blueprints marked up (after I had to go through a full explanation as to why they aren’t blue)
Just tell her that they USED TO be blue. Still can be, if the paper can be found. Last time I needed to make one, I didn't have a machine- I had to place the drawing over the blueprint paper & cover it, take it to direct sunlight, guess at how long it needed to be exposed before covering it again, then take it to a room with no sunlight to expose it to ammonia.
Good times!