It seems to depend on the design - how close you are to the design limits and how much copper is exposed on the outer layers.
A message someone got from JLC for an open source project recently:
> When the copper pour is less than 30% of board area, we suggest to keep at least 0.15mm trace spacing.
> Or the dry film debris might have chance make short circuit, it will make quality control more difficult
It seems to depend on the design - how close you are to the design limits and how much copper is exposed on the outer layers.
A message someone got from JLC for an open source project recently:
> When the copper pour is less than 30% of board area, we suggest to keep at least 0.15mm trace spacing.
> Or the dry film debris might have chance make short circuit, it will make quality control more difficult