Rodger,

Yes, PE is Polyethelene or RC. You discovered 312 Semi-Matte/Pearl. ADOX 312 Pearl has a high surface gloss. Using a color head, 312's light surface texture hids -135 Tri-X grain on 11x14s. The D-max is slightly less. The white base helps prints project through glass. I was always a fiber guy but for wall mounts I am getting converted to ADOX 312 pearl.