What is this and how to handle it?

[Jon Bang]

When i am scanning films, super8mm, this happens in between. The film is in focus and everything else is OK, but sometimes the film gets like its out of focus and like there is some kind of cover in front between the film and camera. Is it a beginning vinegar-syndrome or other chemical process going on?

[Ken Finch]

Difficult to tell without details of how you are capturing the film. Could it be condensation on the camera or projector lens? Ken Finch.

[Jon Bang]

Its a "normal" frame-by-frame-capture with scanner made by venturaimages. The camera is ximea xic. The picture is clear other places, no signs of condensation. Framerate is about 20/fps here.

[Nantawat Kittiwarakul]

What about the physical condition of the film itself?
What's the duration of that blurry mess? Just a few frames in a while or tens/hundreds in succession?

[Terry Sills]

From your description it sounds like the film has some buckling which is often a symptom of VS, but it should be obvious from a physical examination of the film when it is wound on the reel.