Seeking Info about TTY 3641

I found a box of 32 year old Teletype (model 33) printouts that was still yellow. (I wish I could've kept them but space was at a premium and they were tossed. Lots of BASIC programs.)

I think the discoloration will vary depending on storage. A newspaper left out will age far faster than one put in a box.

I kind of suspect common Teletype paper rolls were made of newsprint like materials, that is, cheap paper. A business or school would go through considerable volume of them almost all of which would end up in the trash. No point to having high quality. Indeed, I think my school got away from yellow altogether and got rolls of straight newsprint. It was lousy paper but it sufficed for the needs.

For businesses doing more important work on their Teletype, they would have form feed with form paper that presumably was of higher quality and more long lasting.

Are you sure it's thermal? I would suspect that's more expensive. I suspect they're low grade bubble jet printers. The image fades just from humdity if in your shirt pocket or wallet or folded over. I don't care about supermarket receipts, but receipts for expensive items do matter.