Bob:(posted 8462 days ago)Unless there has been a change, the SFW stuff is respooled movie film with an anti-halation layer on the back that is not fully soluble in C-41 chemistry, and it does indeed mess up the entire batch of chemicals in a C -41 process. Almost all films have antihalation backings to prevent reflection of light back thru the emulsion creating fuzzyness, but standard films have layers that are fully soluble in regular developers or even water.
If you really want to try it, get some and get a small C-41 home kit. If it works, keep doing it, because no matter how much you seem to know, or cry or cajole, any sensible minilab operator will not touch it.
Save a few bucks and cry.