My Durst 138 Setup

[Larry Kellogg]

Yes, but the prints are incredibly sharp. It's a style. Hans Namuth in the Darkroom 2 book put out by Lustrum Press explained why he used a point source. He liked the way the transitions from light to dark are very sudden.

I'm all set to try out a point source using a socket adaptor and halogen bulb. I just need the transformer.

You have to be careful when focusing with a point source because you can actually focus on different layers in the emulsion. You don't want to focus on the base layer, LOL.

[Luis-F-S]

Luis,
Well, I've never owned an Opal bulb.....

Larry, the G40 which I thought you had used is an opal bulb. L

[JMB]

Yes, but the prints are incredibly sharp. It's a style. Hans Namuth in the Darkroom 2 book put out by Lustrum Press explained why he used a point source. He liked the way the transitions from light to dark are very sudden.

I'm all set to try out a point source using a socket adaptor and halogen bulb. I just need the transformer.

You have to be careful when focusing with a point source because you can actually focus on different layers in the emulsion. You don't want to focus on the base layer, LOL.

Not sure, and I naturally have no personal information, but I believe that Brett Weston used a 138 with a point source of some sort for some of his work. Others on the forum, I believe, have experimented with optimizing a 138 point source in various ways. So there is information out there. Would you keep me posted on your discoveries? Although I am increasingly more focused on contact printing, I remain interested in setting up my own 138s-- one as some sort of point source and the other with an Aristo cold light. In any case, I became fascinated with the 138 condenser set up after examining some 5x7 prints made with one (I believe from medium format negatives). The prints had a rather unique, stark look that interested me.

[Ginette]

Here are a few pictures of my Durst 138. I installed an Ilford 500 head and RH Designs Analyzer 500 timer. The 138 has an adaptor box to raise the head up high enough to cover a 5x7 negative, due to the inverse square law of light falloff. I use the 6x7 mixing chamber.

Ginette from the forum provided the measurements for the adaptor box, as she had one of the originals from Durst. Jay from NewVision photo on the Bay fabricated the box for me. Jay has been a great help in getting my rig up and running. A big thanks to Ginette and Jay!

Exposure times are reasonable, actually quite short. I love the probe on the timer as I can sample densities of a negative and get a decent print on the first try, no need for test strips. I use this setup on everything from 35mm to 5x7.

The timer does split printing for all exposures, handling the times for you.

The original adapter was made by Ilford like the many others they done for adapting their 500 head system to various enlargers.
I had this adapter in my stock but didn't know what this metal part was for! This is a square adapter with a medium format hole on top that came to me with Ilford 500 items from a guy who have Beseler and no Durst, so I didn't make the association with the Durst 138 (5x7). This is from a discussion on the French forum Galerie-Photo that a member, Jean-Pascal, send me pictures and info about this adapter that I realise that this was the exact part I have (and wish to dump in some occasions!).
I got also confirmation that the system cover 5x7 format with the use of the Ilford white medium diffusion box by Steve Sherman. You can see some pictures of Steve enlarger bought from Yale and some discussions about in this recent ForSale topic http://www.largeformatphotography.in...ead.php?117898 So by two differents sources I can mount the adapter the way it is supposed to be with the right accessories.
I had also some discussions in the same period with Larry who wish to buy a Durst 138 and tell him about the Ilford head that can be mounted on the Durst. So Larry contact Jay (NewVision on eBay) and all three was in contact about the adapter. I can confirm that the adapter replicated the exact dimensions of the Ilford original as I sent pictures with digital caliper readings to Jay. He sent me an adapter for my help, it is now sold with a Durst 138 and Ilford head to Bill (a Canadian member here).

Some facts about the adapter:
- You remove the door and the mirror of the Durst head, you place the adapter in this space, it will place automatically over the condenser slots. Adapter have 4 walls so it cover also the opening of the Opal bulb.
- You have to use the medium format Ilford box, the hole on top of the adapter have this size. The right box to use is the one with only 4mm below the small bumpers, not the long Beseler box that extend 35mm under the small bumpers.
- It is not the box that will cover the right format but the condensers good usage for the right format. 2x 240mm for 5x7, 240/200 for 4x5, etc. the same way you will use yours condensers with the Opal bulb. In my sense (but not tested) it will give the same results that the opal bulb with the condensers but with the convenience of the Ilford 500 head filtering system.
I don't think this adapter can perform well in diffuse mode, it is done to be use with condensers. The inside is flat black and without the condensers, I don't think it will cover 5x7 and maybe not the 4x5 either because of the neg distance from the light source. If you wish to use the Ilford on the Durst without condenser, you will have to remove the condenser housing, put a metal plate over with the Ilford head right over the neg stage and with the 4x5 diffusion box, it will cover only 4x5.

If you need any other info, just post, I will try to answer.

[Larry Kellogg]

This thread:

http://www.apug.org/forums/archive/i...p/t-25125.html

also states that Brett Weston used a point source enlarger in his work. So, perhaps that is true.

I look at a point source setup as just another tool to use with certain negatives. Now, if I could just get a Varipoint.

That thread also says that the Opal or Thorn bulb is diffuse at its origin, which I believe is true, after all, the bulb is coated.

There is also a lot of discussion over whether a point has a higher resolving power. I don't know the answer but I want to find out.

The little halogen bulb I'm going to use in my Durst is obviously not coated and should be an excellent point source of light.

[Ginette]

Randy, I'm curious about your ideas, share when you get something working.

ic-racer, I use the 6x7 mixing chamber which has a little white diffusion panel at the bottom. You can see it in this picture. Attachment 133374

Yes, this is a bit of a hybrid system, combining the dichroic head with condensers. The 500 head uses two 300 watt halogen bulbs, so it puts out plenty of light.

Larry, on this picture, you miss the medium format plate that keep the diffusion box at it place in the Ilford head and that will keep away from unwanted light leaks.

[JMB]

Okay. Good. Miller is one of the guys that I had in mind re: Durst 138 point source experiments. Please let me know how your halogen works out.

[Larry Kellogg]

Good eye, Ginette, this picture was taken before I received the adaptor box and plate. I was just testing the head to make sure it worked. I'll take another picture that shows it in its final configuration.

[Larry Kellogg]

Ok, I didn't have time to take the head off, but here is a picture I shot by taking out both condensers. You can see the plate that goes around the mixing chamber.

[ruilourosa]

Hello!!! I didn´t like the blower noise of my 138 with cls 300 so i installed 100 w leds with these heat sinks, it fitted perfectly: http://www.ebay.co.uk/itm/1113653823...%3AMEBIDX%3AIT

A bit of a delay in the power on but not that abnormal and the light is amazingly actinic and uniform


CHeers