White spots

[Dep]

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I have experienced this problem in photos where there was no moisture in the air.
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It's not just caused by moisture, it's actually more common with fine particles of dust or grit, especilly silica (glass!) rich dust as found in sand mines and our local sites (underground stone quarries)

And it was these being mistaken for supernatural activity that prompted my comment on another thread about pseudo-scientific paranormal invesigators.