White dots black dots

I did read on here a little while back, that on condenser enalargers, an white dot is dirt on the condensers and a black dot is marks on the film.
Any offers on that.

Graham

Sharp-edged dots, white or black, are on the film, or the glass in a glass carrier. Black spots are clear areas on the film.
Usually, dust on condensers is pretty soft and hard to see in prints.

I've occasionally seen white spots on prints that are caused by paper issues. Usually these aren't sharp-edged, and they seem to be caused by fingers (fingerprints) or chemical build-up on print tongs. Once or twice I've seen sharp-edged white spots that are caused by chips in the emulsion (this becomes clear under a loupe). I've put this down to handling damage of an unknown variety, but I can't be 100% positive of that.

Sharp black dots on your prints are holes in you negatives emulsion

There are all sorts of reasons they could be there - but as I found out from bitter experience with sheet film - it is usualy from dust or other contaiminents when I was loading my Darl Slides.

I am not sure how it gets there or where its come from but I now rigerously clean my Changing Tent with a clean, well washes damp linen Tea Towel before loading film.

Martin

bdial said:

Usually, dust on condensers is pretty soft and hard to see in prints.

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This will depend on where on the various condensers the dust, etc are. They can be fairly sharp if on the condenser surface near the film plane, or can be large lighter areas seen in areas of even tonality (such as sky) if on the top of the top condenser.

I have seen relatively sharp black lines on prints caused by metal tongs while the print is in the developer (the paper emulsion is pressure-sensitive when in the developer -- pressure will "expose" the paper.) However, these marks vary from print to print and thus easy to differentiate from pinholes on negatives.

Agfa papers use to occasionally have perfectly round small circles of white -- emulsion coating flaws (bubbles).

So there are sorts of sources of white and black marks in the process!

Vaughn