[Retlaw]

Originally Posted by annesingleton

Looking closer, the men seem to be covered in muck - could be sawdust, and their clothes definitely aren't too clean - one has a greasy stain on his trouser leg.

Looking closely at an enlargement most of those tiny specks appear to have come from the original negative, its surprising how much debris there is in water, especially when processing film, I had a micro filter, for the water I used to process negatives. Look closely at their faces, and you can see those tiny marks caused by dirty water, they can even attracted dust whilst the emulsion is drying after being developed.
Retlaw