Hi Loris,

I'm fine now,thanks!

No doubt your help to me is enormous.I'll always be grateful for that.

It was solved by chance.Usually I would coat paper that has been exposed to air in the room for 24 hours(humidity is about 70%). Someday I was busy and didn't coat it till three days later. And the result was different. It seemed the problem was the humidity in the paper. Does it sound queer?