Someone having a Durst Laborator 900?

[JuanMi]

Hello you all!,
I recently purchased a Durst Laborator 900 enlarger (very big and heavy!), but I have no manual.

Although the basic adjustments and functions are the same as other enlargers, there are a couple of things which escape me! Can someone please help me to understand them?

For instance:

.- At the base of the "mast" there is a "focus variator" (with two wheels) and a mm scale. It seems to me something related to the use of easels or such things... as the enlarger seems to keep focus even if the head is moved... in order to adjust the height of the easel surface...

.- The mast has different scales... (4 in total) does any scale has something to do with exposure compensation depending on the height of the head?.

.- Do you read such scales from below the head? (what do you use for reference?).

.- The 50mm lens aperture is sticky and would like to clean it. It is holded by a BIMAPLA holder. May I just unwind it (difficult to access it as it is very protruded) or have to dismantle the whole bimapla?...

Well I have more questions, but I don't want to bother you too much! .

Trying to post a pitcture...

Best wishes!

Juan Miguel

 

[Claire Senft]

It is a autofocus enlarger. The focus variator is for setting the thickness of the easel.

 

[JuanMi]

Thank you Claire!
So it seemed to me... although it does'nt keep in focus all the way, now I know what it is for.

Do you use a Durst laboratos?

Thank you again!

Juan Miguel

 

[Claire Senft]

I used to have an L900 bac k in the 70's. my memory is a bit vague. Try doing this: set the focus variator to the thickness of your easel. Use at least a top glass on your carrier. Bring your enlarger head to a smal print size. Focus with a magnifier. Raise your head to say 11x14 size. Is the print still sharp?

 

[JuanMi]

Hello and thank you again Claire,
Yeah! you nailed it! Once manually focused, it keep the focus all the way (incredible!). I will need some years to understand how it does the trick, but it does it! .

I didn't knew that L900 were from the 70's it looks like a little bit more modern... It seems so strong and professional... compared with my former Krokus Mini M enlarger...

Your memory works fine! I just don't want to bother you with such enlarger questions... but... thank you again!

Best wishes,

Juan Miguel

 

[LikeAPolaroid]

Revitalising this thread in the hope to get an answer to my question.

So, you here are saying to "manual focus" first. How do you do that?

 

[koja]

Bump. The same problem here. Focus variator seems very easy to go to lower values (as the weight of the head is pushing down) but it is rahter heavy tu lift it up. I am not sure if there is no other trick, I don't want to ruin it...

 

[rockphotographer]

problems with the focus/lock on L900

I have an L900 and the CLS450 head. The focus knob doesnt seem to do anything and the head lock (column lock) knob doesnt seem to lock the head.....

What should i tinker with to get those working? Any thoughts?

Thanks

 

[LikeAPolaroid]

After I wrote the post above I figured it out. Pretty easy actually.
Undoing the right knob will unlock the column so you can raise it with the left knob.
You need to raise/lower it until you get a focused image on your easel. What I generally do is to raise it (yes, it's heavy but not too much and it should go smooth anyway) until the height indicator reads the easel height, approximately. Then, with a focus finder and a negative in the holder, I fine-focus on the grain. Then you need to lock the column and the enlarger will keep the focus no matter where the head is. That's the "auto-focus" mechanism.

In some cases though, when the column is at the highest position or in the lowest position, focus gets lost. There is a procedure to recalibrate the autofocus mechanism but it involves opening the head and tinker with the camshafts. The easiest way to work this around is to act on the lens holder, rotating it until you get the right focus.

 

[rockphotographer]

Yeah...mine has one knob...nested. There's an outer knob that says it locks the head on the column....and the inner knob is the focus knob (both on the right side).

Mine won't lock in position particularly....and the focus knob doesn't move the head or the lens stage...any thoughts?

I also need a carrier for 6x6 and need to know what carriers will work.

Thanks.

Charles

 

[rockphotographer]

Here's my enlarger (Durst L900...cls450) see the youtube video to see my issues with mine....

http://youtu.be/FPtl8OIliYY

If any of you can help me...please toss me an email or a PM.

 

[rockphotographer]

Seems I've figured out my focusing issues on my l900. I use the knurled ring around the lens to set focus at a given height, then the enlarger does the work when moving the head up and down. It holds focus beautifully now ! I don't know what the knob on the right of the head is for.....

http://youtu.be/FPtl8OIliYY

That is my enlarger...feel free to take a peek and let me know any hints you might have.

Thanks!

 

[ic-racer]

I suspect that knob is the fine focus knob.

 

[rockphotographer]

I suspect that knob is the fine focus knob.

Yeah...I'm assuming that's what it's for, but it doesn't do much other than move the head upward a touch...it wont come back with that knob....odd.

 

[ic-racer]

Yeah...I'm assuming that's what it's for, but it doesn't do much other than move the head upward a touch...it wont come back with that knob....odd.

Perhaps there is a deteriorated rubber wheel.

 

[LikeAPolaroid]

Chiming in now - hope issue was solved in the meanwhile.

To properly set the autofocus to work, you need to raise/lower the entire column by unlocking the column base with the focus variator handle on the right and raising it/lowering it with the handle on the left, and then lock the column again. In theory, the height indicator should correspond to the height of your easel - or zero if you don't have any easel. In practice, put a test negative in the carrier, and use a standard focus finder to set the column height.
Once this is set, L900 keeps the focus when you raise/lower the head, for about 2/3 of its excursion, mainly in the central zone. It may lose focus at the max or min height. In that case you need to adjust the focus with the knurled ring around the lens.

The two knobs on the right of the head are: the outer (larger) one is to lock/unlock the head, the inner (thinner) one is to do micro movements when the outer knob is locked. In practice, you unlock the column with the outer knob, set the head at a given height, lock the head with the outer knob, and then use the inner knob to precisely set the column height for a certain enlargement. Those two knobs are NOT used for focusing, but only to set the enlargement.

Looking at your video it seems that the outer knob does not lock the column, therefore the inner knob can't be engaged. It should not be a major problem to fix. I own the repair manual so if you still haven't solved send me a PM and I will try to help you.