TIL the original blueprint process used ammonia and sunlight

I was reading an old drafting textbook from the 1970s I found at a library sale. It said draftsmen used to make blueprints by exposing treated paper to sunlight through a vellum drawing, then fixing it with ammonia fumes. The whole shop would smell like it. I had no idea the name came from the actual blue color of the final print. Has anyone here ever used that old method, or know someone who did?

3 comments

3 Comments

barbara_campbell2mo ago

Wait, the whole shop just permanently smelled like ammonia? That sounds absolutely brutal to work in every single day. I can't imagine having a headache from the fumes on top of trying to do detailed work. It's wild to think that was just a normal part of the job back then. Makes you appreciate how easy we have it now with digital files and regular printers.

the_thomas2mo ago

My granddad worked in a print shop in the 70s and he told me the ammonia smell from the blueprint machines got in your clothes for good. You're right barbara_campbell, it was just accepted as part of the deal, like a constant chemical hangover. I read that some old school printers actually lost their sense of smell over time from constant exposure. It really does make hitting 'print' on a PDF seem like a miracle by comparison.

seth6832mo ago

That "constant chemical hangover" line from the_thomas really hits home. People didn't just lose their sense of smell, they traded long term health for a paycheck without even knowing the full risk. It makes our current office complaints seem pretty small in comparison.