All the local pro labs in my area mount my provia processed slides on plastic mounts as opposed to the carboard type. I have read that plastic slides may not hold their value as well as the plastic type? So this brings me to this question. If cardboard is the preferred type of mounting does it matter who processes it? It seems that almost everyone on this forum uses a local lab.
For example, when you process K64 you know you have kodachome slides. With other slides types, you have no real way to prove what type of slide film it is derived from unless you take it out of the mount. Even if there were other labs that could process K64, my guess is that most would still use Kodak because of the mounting? If this is true, why wouldn't Fuji users use Fuji processing?
I hope this isn't too confusing!