White film on leaves?

[vlhart]

So I've got a few orchids with what looks like white film on their leaves. In the pics below--the phal has what looks like sort of a faint white coating on all the leaves that covers the whole surface of the leaf. Another phal I bought with it also has a bit of the same thing. I tried using milk to polish the leaves which didn't have an effect. And then tried rubbing alcohol which also didn't have an effect.

The ascocenda has what looks like a different type of white stuff on the leaves though it's a little hard to see from the pics. It's more in spots and strings but it doesn't wipe off or come off with alcohol or even scratch off. It also appears to be spreading a bit. Not sure if it's related to the brown leaf tip either. (sorry for the blurry pics)

Also--both of these plants are isolated from each other and had some of this when I bought them (separately).

Any ideas what could be going on with either? Thanks so much for your help!