Durst 138 Laborator Point Source Information

Kirk Tadox · Jul 6, 2015

Hello Everyone,

Thanks for taking the time to read this post. I'm hoping to find some recommendations for good sources of information regarding point source enlarger set ups, either generally speaking or specifically with the Durst 138 S Laborator in mind. A website, book, or even better someone with experience using their own system would be greatly appreciated.

In researching the interweb for awhile now, comprehensive information seems largely absent. I have read the forums here and other places which largely seem to be composed of comments disapproving of the technique or the statements that the same results are obtainable by other light sources (which I find wholly untrue by experience), but otherwise very little applicable information.

A few questions that come to mind are:

The 138 manual states that Latico type T condensers and negative carriers are required for point source. What is their role? Is there an alternative? Also, a guy on eBay is selling two Latico 240 type P condensers right now (for a fortune). He claims the P is for point source but I can find nothing in the Durst literature that mentions a type P condenser. Anyone familiar with the P designation?

What about substitutes for the long extinct Durst PULAM/VARIPUT and ZIRLAM/ZIRTRA lamps? Recommendations online range from tungsten to halogen to halogen-tungsten, 12v auto headlight, LED, 130 volt variabledoes anyone know of a good source detailing the specifications of the original lamps for comparison? What about the most crucial aspects for selection, i.e. actual size of point (filament, etc.), orientation, field of illumination, etc.

Regarding the lamp, I have a voltage controller I've been told is good for adjusting luminance value so time can be controlled while exposing wide open. Have you used this technique? Approve/disapprove?

Some people mention building a reflector for the lamp. Is this more about increasing directional output of lamp or shaping a wider field for coverage? Any examples around?

I have more questions then can be listed here, and again would welcome the opportunity to communicate with someone with direct experiencemaybe we could discuss compensation of some kind?

$1,362.50 for the Durst retrofit kit is just too dear at the momentlooking for a quality alternative.

Thanks,

-Kirk

Marco Buonocore · Jul 6, 2015

One of the Lustrum Press "Darkroom" books had a chapter written on point light source. I can't recall if it was volume 1 or 2. If you've not read that, it might be useful.

Kirk Tadox · Jul 6, 2015

Thanks for the recommendation. I have not read these, but found inexpensive copies online already. They sound good all around.

shoot6x7 · Jul 6, 2015

Jensen optical in the states are a very good resource.

http://www.durst-pro-usa.com/products.php

Marco Buonocore · Jul 7, 2015

Kirk, have you seen this thread posted in 2004?

(there was a url link here which no longer exists)

There's an article mentioned in post #17, published in Darkroom Photography Magazine. I wonder if anyone has a copy of this article?

I have another question for anyone with experience with point light sources: do they work with variable contrast paper, or is it intended for graded paper only?

Thanks.

Kirk Tadox · Jul 7, 2015

Thanks for the info. Marco, i did see that mention and headed straight for eBay. Found a guy selling a couple of issues from that year but not that issueof course. I sent an email out the original publishing house to see about back issues but seems like a hail mary at this point.

Paul Howell · Jul 7, 2015

Marco Buonocore said:
Kirk, have you seen this thread posted in 2004?

(there was a url link here which no longer exists)

There's an article mentioned in post #17, published in Darkroom Photography Magazine. I wonder if anyone has a copy of this article?

I have another question for anyone with experience with point light sources: do they work with variable contrast paper, or is it intended for graded paper only?

Thanks.

A number of years ago I converted an old Federal 6X9 to a point source to enlarge 35mm negatives taken in the 60s, I wanted high contrast, sharp with gain. I got all 3 in spades, so much that I reverted back to standard condenser with white frosted blub.

I used a clear halogen lamp I found at light blub store, the filament as small, one reason I picked the Federal is that I raise and lower the lamp to find the spot that I did not see the filament shadow. I cut out a 35mm mask of sheet metal below bottom condenser and above the lens. Federal made both single and double condenser enlargers, I had a model with double condensers, the lamp was very hot, I had a round sheet of glass cut to act as a heat barrier to the top condenser.

I painted the interior of the lamp housing flat black with barbecue grill paint.

Best lens for 35mm was the old 2 inch Federal that came with the enlarger, a modern lens increased contrast.

I tired grade 2 paper, some Gailliera grade 1 that I had on hand and at the time Agfa VC at 00, still too much contrast, and the grain was huge anything over a 5X7 was awful. A low contrast 6X9 gave good results at grade 1 or2.

I know of a few who converted Durst 4X5 enlargers by using slide projector blubs and using a blower to cool the lamp housing, don't know the details.

Kirk Tadox · Jul 7, 2015

PDH, thanks for the firsthand account. I've been looking into halogen bulbs and wondering about wattage, but I'm most curious about alignment. The enlarger I'm using has full movements on the light source, and double condensers that are fixed. I've read in another forum about it being necessary to have the ability to move both in order to "focus the point source on the nodal point of the lens" which I'm uncertain how to do, as well as whether or not it is the correct thing to do.

My particular enlarger must have been used for point source at one time as it did come into my hands with a squirrel cage blower already affixed to it's exhaust. The light chamber is also already painted black as well.

In my original post I tried to not go into the aesthetics of point source because I really am eager to get technical information, and thought it would invite a different discussionbut as I recently told a friend...

"Interesting that there are seemingly so few people using the technique. I knew a photographer who ended up working as a master printer for an art house in Los Angeles years ago, who also did a lot of work for the entertainment industry before things went digital. He made a series of point source prints on the exact enlarger I'm talking about that always stuck in my mind out of a sea of other great images. I'd say they were stunning, but stunning sounds too smoothly great. Striking would be a better word. The degree of sharpness they approached was not friendly, not even pleasant...in fact it was raspy and harsh to a degree that I think a lot of people probably would not appreciate, something like a visual pile of cactus needles.

Sharpness, acutance, and the like are discussed frequently in these forums. Barry Thornton's "Edge of Darkness" is a book that shows a remarkable degree of sharpness in the images and I've seen others like them, but the point source images I've seen are hyper real somehow, blazingly clearif the prints are large enough the clarity itself can be intimidating, almost like your eye doesn't get a moment of rest from the overwhelming degree of informationjust my two cents but there is something very special about the technique when applied correctly.

There's a lot of talk about the difficulty involved because every imperfection from negative to carrier to lens, condenser, light source, papershows. I think there is a great degree of challenge there but for me the firsthand experience of seeing it all come together correctly was too unique to pass up."

Paul Howell · Jul 7, 2015

Kirk Tadox said:
PDH, thanks for the firsthand account. I've been looking into halogen bulbs and wondering about wattage, but I'm most curious about alignment. The enlarger I'm using has full movements on the light source, and double condensers that are fixed. I've read in another forum about it being necessary to have the ability to move both in order to "focus the point source on the nodal point of the lens" which I'm uncertain how to do, as well as whether or not it is the correct thing to do.

My particular enlarger must have been used for point source at one time as it did come into my hands with a squirrel cage blower already affixed to it's exhaust. The light chamber is also already painted black as well.

In my original post I tried to not go into the aesthetics of point source because I really am eager to get technical information, and thought it would invite a different discussionbut as I recently told a friend...

"Interesting that there are seemingly so few people using the technique. I knew a photographer who ended up working as a master printer for an art house in Los Angeles years ago, who also did a lot of work for the entertainment industry before things went digital. He made a series of point source prints on the exact enlarger I'm talking about that always stuck in my mind out of a sea of other great images. I'd say they were stunning, but stunning sounds too smoothly great. Striking would be a better word. The degree of sharpness they approached was not friendly, not even pleasant...in fact it was raspy and harsh to a degree that I think a lot of people probably would not appreciate, something like a visual pile of cactus needles.

Sharpness, acutance, and the like are discussed frequently in these forums. Barry Thornton's "Edge of Darkness" is a book that shows a remarkable degree of sharpness in the images and I've seen others like them, but the point source images I've seen are hyper real somehow, blazingly clearif the prints are large enough the clarity itself can be intimidating, almost like your eye doesn't get a moment of rest from the overwhelming degree of informationjust my two cents but there is something very special about the technique when applied correctly.

There's a lot of talk about the difficulty involved because every imperfection from negative to carrier to lens, condenser, light source, papershows. I think there is a great degree of challenge there but for me the firsthand experience of seeing it all come together correctly was too unique to pass up."

My old Federal did not have adjustable condensers, just the lamp, my bulb was a 200 watts, cylindrical, long and narrow. I know that Omega and Besselor made point source heads, as I recall for printing from Microfilm, but I also recall that AA used point source to print from 35mm.

For cost of upgrading your Durst you might want to make a DYI using a Federal, if you can find a double condenser 4X5 it is doable wont be in for more a $100 or so.

Perhaps if I had a 4X5 may have gotten better results.

Luis-F-S · Jul 24, 2015

The 240P condenser is for horizontal Projection, NOT point source. Point source uses the T coated condensers as you stated. A complete set sold on the auction site for a buy it now price of $399 a month or two ago if my memory serves me right. I thought about buying them due to the price, but I have no interest in point source lighting. Post some photos of your enlarger and we may be able to give some suggestions. L

Kirk Tadox · Jul 25, 2015

Thanks for the clarification on the Latico glassit seemed a little mysterious. In the interest of expediency, here are some crummy, cell-phone-flash images of my enlarger. I don't think there is anything out of the ordinary about it, just like the other 138's I've seen anywayon another note, a school near me recently either re-did or destroyed it's color lab. I drove by and saw several small Durst medium format enlargers, 2 giant Beseler's, and a couple of Agfa roller transport developing machines of some kind (not much color experience) sitting by a dumpster on the side of a building. My excitement dwindled when I got closer and saw the stuff had probably been sitting there a week, and packs of bored teenagers must have smashed nearly everything there into oblivionit was a total waste. I did however find one of the color mixing heads in good (looking) shape along with some controllers and other various bric a brac that I have no use for, but could not leave there. I even took what looks like a small color developing machine with crumbling rubber rollers thinking it might be brought back to life somehow. I mention this here because I also found a box of NOS bulbs that must have been used for projectors, enlargers, and the like. There were several high-wattage, halogen type clear bulbs that must span the last 30 years in origin. Some are long and skinny, others more of a capsule type. I'm pretty sure one will make a good point source but am still seeking more references on bulb selection to be sure...

AgX · Jul 25, 2015

Luis-F-S said:
The 240P condenser is for horizontal Projection, NOT point source.

What is the difference between horizontal and vertical projection concerning the lighting system?

Durst 138 Laborator Point Source Information

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