Replies
Welcome, guest
Join CrazyEngineers to reply, ask questions, and participate in conversations.
CrazyEngineers powered by Jatra Community Platform
-
@ramani-VR4O43 • Jan 28, 2013
When we were students and during early days of work (1950-60s) drawings were actually made by hand on a translucent tracing sheets using Indian Ink. These were reproduced in an blue printing machine which produced a negative drawing with white lines on a blue background (hence the name).
I have myself used one of these ungainly machines.
It was also called ammonia prints. Some sheets will give sepia toned prints.
Here is more info:
<a href="https://en.wikipedia.org/wiki/Blueprint" target="_blank" rel="nofollow noopener noreferrer">Blueprint</a>