What's up with my Durst L1200?

[Henry Yorke]

I've got a Durst L1200 with a CLS 450 Head - and I've been having the darnedest time controlling the contrast with this enlarger. I routinely find myself having to print at Grade 5 (with fiber, VC paper) in order to get anything approaching blacks and whites. I've never had any luck printing at Grade 3. And even at 5, the contrast in the print seems weak.

I've tested my safelight, made sure that I have fresh chemicals (and that the chemicals aren't cold) and VC paper, and I'm using well-exposed negatives.

I pulled out my old Saunders LPL6700 and exposed the same 6x6 negative on it - with great results. I bought this L1200 about seven months ago but have just gotten around to using it within the last little while.

So - what's up with my L1200 enlarger? Is it possible that the filters in the CLS 450 head are getting old?

 

[Nicholas Lindan]

I had a similar problem - it turned out the enlarger's lens was badly fogged and needed taking apart and cleaning.

 

[Sparky]

i think making a contact print of a step tablet on VC paper will reveal whether the problem is with the optical path or the filtration.

 

[paul_c5x4]

How often do you change the lamp ?

Most are only good for 50 hours or so before the quality of light drops off. A new ELC lamp will only be a few quid/bucks, and it is always worth having a spare on the shelf.

 

[dorff]

How often do you change the lamp ?

Most are only good for 50 hours or so before the quality of light drops off. A new ELC lamp will only be a few quid/bucks, and it is always worth having a spare on the shelf.

It is possible, but not likely, that the lamp is the problem. I would suggest that the OP checks the following:
1) Lamp (because it is the easiest thing to reach and/or fix)
2) Lens for fogging, fungus or haze. If the lens is dirty on the outside, use pure ethanol or propyl alcohol with a lens cloth to wipe it clean. If on the inside, it should go to a technician.
3) Check whether your light source assembly is properly aligned, all the lenses, diffusers, etc. are in their proper positions.
4) Make sure that your safety filter hasn't gotten stuck in the light path. This happened to me, and it took me a while to figure it out, I am embarrassed to admit . Okay, in defence, it was when I was starting out anew after a fifteen year absence. The lever that swings it out had disengaged, so I couldn't figure out how to get it out of the way until I opened it up and did some corrective tinkering. BTW, if you print on VC paper, then do not use the red safety filter in any event as it may not be safe for your paper. VC paper requires an orthochromatic (green-brown) filter. This at least is how I have it from my limited research on the subject.

My bet is 4, then 2, then 1 then 3. Let me know what you find .

Edit: I should have added that my enlarger is a Durst M605. It cannot be much younger than your L1200, so I do not think the filters are too old, unless the enlarger was standing in sunlight and the plastic has been UV damaged. Your L1200 probably has the same red safety filter that my M605 has. It can be removed without too much fuss. It is a bit like a gall bladder - one can live without it if one has to.

 

[Henry Yorke]

Thanks, everyone, for your thoughts - I shall use your suggestions to attempt to figure this out on the weekend.

 

[skahde]

The lamp is easy to access and the filters are just under it. Take the lens out and shine a light through the filters from below to check for any problems. If they are clean and clear they shouldn't be the source of your trouble.

 

[dorff]

last night I had to change the lamp on my M605. In the process I managed to knock the safety filter inline again, LOL. After two blank test strips the penny dropped. The point here is that I cannot easily see from the colour of the light whether the safety is in or not. One has to check on the enlarger itself. The more I think about it, the more it seems the safety filter could be your problem. A dirty lens could also give the symptoms. Do the prints look fuzzy or just flat? And what are your exposure times like? Minutes? Then it is definitely the filter. A fogged lens will not reduce exposure that much.