[samlinnfer]

You can buy phenol free paper

https://www.pca.state.mn.us/business-with-us/bpa-and-bps-in-...

[1e1a]

There's also this which works using a purely physical process: https://www.koehlerpaper.com/en/products/Thermal-paper/TH_Bl...

[thomascountz]

Check out some results here: https://thermalprintcameras.wordpress.com/blue4est-paper/