developing - What caused these strange patches on developed film negatives? - Photography Stack Exchange

Blotchy marks on negatives: Film Photography Talk Forum: Digital Photography Review

Thinking about spending a stack of cash on a film camera? Read this first! - 35mmc

Molecular Expressions Microscopy Primer: Photomicrography - Black & White Film Processing Errors

Inconsistent defects/black spots on negative, first time developing with these chemicals : r/Darkroom

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35mm - Film photography - what causes the following effect/error on a single frame of a developed roll of film? - Photography Stack Exchange

Marks on negatives - developing or camera?

film - Weird blotches on old negatives and slides? - Photography Stack Exchange

I keep getting these dots in my negatives and sometimes it erases the whole image but the dot. What is causing this to happen to my negatives when I am developing them?