Condensor enlarger/spots on print

[markbau]

I've been asked to fix a LPL 7700 condenser enlarger. The problem is that random faint white spots appear in the sky area. I tested it without a neg in the carrier and there are indeed small white spots and smears all over the print. I have taken the lenses out and cleaned them as best I could and double checked that the lenses were put back in the correct configuration, I changed MG filters to see if I could get the same pattern, I got the same problem but the spots were in different places. My question is, do MG filters have to be spotlessly clean in a condenser enlarger? How hard is it to keep them so clean?

 

[Marco Buonocore]

Are the filters above or below the lens, out of curiosity?

I would try making a print without any filters at all - see if there are any marks on the print. If there aren't marks, the answer is the filters. If there are, the the problem lies elsewhere.

With all that said, I don't pay too much attention to how clean my filters are - I've never noticed a problem.

 

[gone]

With condenser enlargers everything in the light path has to be spotless. The bulb, the condenser, the filter (if any), the negative carrier if it's glass, and the negative. Not to mention your paper, but that's probably OK. If you're making large enlargements tiny dust can get magnified quite a bit. One learns to get pretty good at spotting :}

Double check all that. Smears on the print is is odd. I assume that the lenses are spotless?

 

[markbau]

The filters are above the film. Just after I posted I thought "I must test without filters" so will try that tonight. I use a color head so never have to worry about this sort of thing, the filters I used were clean but certainly not spotless!

 

[mike c]

I just had to replace the Ilford Multi con filters on my 138 Durst condenser enlarger , they were scratched and leaving spots and marks in the sky areas. Also like mentioned by momus, even the bulb has to be checked for any marks on the inside coating of the bulb, and the condenser's clean and no scratches. Also the heat absorbing glass, and the glass on a glass type film carrier, condenser enlargers can be a real P in the A sometimes.

 

[gone]

Good idea to test with and without filters. I imagine that anything on the filters will show up on the print. It sure did on my Durst, which had a glass negative carrier that drove me nuts w/ dust because between that and the negative there were 6 surfaces for dust to get on, and that's not counting the condenser and filter.

 

[markbau]

Do I need to take any precautions when cleaning the Ilford MG filters, what solution works well?

 

[mike c]

They do scratch easy, if they are badly scratched it would be best to replace them. I handle them like I would negatives.

 

[norm123]

I have the same problem....so after I clean the negative, the lens. I decided to clean the condenser and it fix the problem