LPL 4550 XLG focus drifting

[NortheastPhotographic]

I'm printing a job and noticing focusing going out between sheets. I'm finding that I have to re-focus every time I make a print basically.

The enlarger is locked down on the column, it's definitely tight. Nothing feels loose to me and I'm not particularly man handling this thing. In fact I'm using a foot pedal to start exposures. The light source is a Heiland LED so I'm not thinking the negative is curling.

Any common weak points that could be tightened up to get rigidity back?

 

[MattKing]

Check the focus mechanism itself.
Is the bellows tightly compressed when you see this?

 

[NortheastPhotographic]

Check the focus mechanism itself.
Is the bellows tightly compressed when you see this?

I wouldn't say super compressed but not very much extended. Making an 8x12 with a 50mm lens from 35mm film.

 

[MattKing]

This is from the manual for a different LPL enlarger - the 7700 - but there may be something similar for yours:

 

[Arthurwg]

I use this enlarger. I generally check focus between sheets but it's mostly OK... When it does go out, I attribute it to heat distorting the negative. Have you seen this with a glass carrier?

 

[mrosenlof]

on my LPL 4x5 enlarger, I find that focus stays good when I change *negatives*. Sorry, I don't have a good idea of what to check in your case. Heat is always possible.

Maybe I would suggest run the fan (power supply on) for a few minutes, put a neg in the carrier and focus carefully.. Let the lamp run for a few minutes and re-check focus. See if focus has changed.

 

[xtol121]

I have the same issue with my 4550 and Heiland LED setup on 35mm negatives using a glass carrier or glassless carrier. It also happens when I print color with the normal halogen bulb. I have tried taking the focusing mechanism apart and putting it back together but it hasn’t helped. I’ve chalked it up to the bellows being too tightly compressed with an 50mm lens even though they don’t look that compressed. I’ve just resorted to checking focus in between test sheets since I’m rarely printing more than 2-3 copies of a print at a time right now. I can’t recall experiencing the focus drift when printing medium or large format but I also don’t print as much with those formats.

 

[MattKing]

You could reach out to Kevin Brown at KHB - the Canadian distributor: http://www.khbphotografix.com/LPL/LPL4x5.htm.
@xtol121 raises a good point - is this issue specific to shorter lenses?

 

[MARTIE]

Is this issue also apparent when using the recessed lensboard?
http://store.khbphotografix.com/Deep-Recessed-Extended-Lens-Board-for-LPL-4x5-Enlargers.html

 

[Ian C]

If you are not using a glass carrier, the temporary bellying of the negative due to the heat of the lamp is by far the most likely cause of the problem.

If you don’t have a glass carrier you can make a temporary carrier with two sheets of glass. Smooth the edges so that you don’t cut your fingers or the negative. Place a black paper spacer cut like a mat between the top of the negative and the top glass to prevent Newton rings.

If this makes the problem go away, then you’ll have isolated the problem.

The two sheets of glass can be hinged along one side with flexible cloth tape.

If the bellows are nearly compressed, as would be likely using a 50 mm lens on a 4” x 5” enlarger, the use of a deeply-recessed lens mount will allow using the bellows in a more-relaxed position.

 

[Ian Grant]

It's worth checking the column as well. The counterbalance spring can cause the head to creep up the column, I've had this happen with a Durst,

Ian

 

[NortheastPhotographic]

So to chime in. I needed to replace my glass pieces in my 4x5 glass carrier, as they were scratched. I got the replacements this week and resumed printing with it. It definitely was just the negative curling..which in theory should not happen because the LED is not very hot..but apparently it's hot enough! The focus remained stable throughout the printing session, so much so that even when changing negatives I would find it still in focus.

 

[images39]

I'm having the same issue, so would like to learn from your experience. I have the same enlarger (actually the smaller 4500 version), and find that I have to check focus every time I make a print, and often have to adjust it slightly.

You mention that using the glass carrier solved the problem. I use the Saunders neg carriers for 135 and 120, which are glassless. I believe the only glass carrier offered by Saunders is the 4x5 carrier. How do you use your 4x5 glass carrier for 35mm enlargements? Do you mask it off somehow?

Thanks,
Dale

 

[NortheastPhotographic]

I'm using the LPL 4x5 carrier and yes, I mask it off with construction paper on the inside of the glass. It still effectively flattens the negative.

I also have the 'masking stage' but I find that it only works for 120 negatives. The blades can't close in enough to work which is annoying.

 

[MTGseattle]

Just so I can make sure I am understanding things (I also have a 4550), Your focus drift was caused by negative "popping?" I am slightly surprised this was happening with 35mm since there is so much metal surrounding the frame with these carriers.
It's good to hear that you have solved the problem, I was watching to see if worn springs or some type of wear in an assembly was the culprit.

That's a bummer regarding the masking stage, I hadn't tried to close mine down that far yet.

As a side note, when running a batch of prints, do any of you tape your negative carriers closed? would that extra bit of tension reduce the risk of "popping" in a glass-less carrier?

 

[NortheastPhotographic]

Your focus drift was caused by negative "popping?" I am slightly surprised this was happening with 35mm since there is so much metal surrounding the frame with these carriers.
It's good to hear that you have solved the problem

That's what I have to assume was happening. I agree it's surprising because the LPL carrier is pretty good and the Heiland LED should not give off much heat. That being said, the glass carrier fixed it so what can I say?

I bet a longer lens would also fix it, just by moving the negative away from the light source. But then the enlarger is fairly high up...