Spotting

What causes spots on negatives? (Damaging white marks on pictures that can be a dot, a line, a streak)

If I understand your question right...

You'll get white spots/lines on prints from anything on

or in your neg that is opaque. Dust and fibers

settling on the neg are the common culprits causing

white spots and squiggles. Use a soft

brush or blower just before printing to eliminate

most of these. Don't blow with your breath because you'll

almost always blow some spit onto the neg, creating

a worse problem. Straight lines are almost always

scratches on the negative itself. There are goopy solutions

that you can put on the neg to "fill in" these scratches

that some people use. I don't like putting anything

foreign on my negs and don't use this stuff.

For any white spots/lines that are in your final prints,

you can use SpoTone and a very fine brush (000 to 00000) to

to hide them. See varous printing

books for descriptions of techniques (e.g., A. Adams,

The Print). With some practice it's not very hard.

Some enlargers, especially condensors, will get dust on the glass elements which show up as spots. If the dust spot is repeating itself from neg to neg then it is in the enlarger. Remove the head and clean all the elements you can get to. Vacume the glass and wear gloves. I spent weeks trying to find the source of a streak on my prints only to remove the enlarger head (Omega D2) and discover a small piece of scotch tape had dryed up inside and fallen onto the glass. Also got rid of a lot of dust. BTW: the tape was from a cardboard shim to hold the glass level, after thirty years it dried up and fell away onto the glass.