Enlarging on Azo

[Donald Miller]

I have a question for those who may have experience with enlarger light sources and enlarger design.

I have three Durst 138S enlargers. I would like to fashion a light source for one of these to allow me to enlarge on Azo.

I have done some peliminary testing with a 15 watt BLB bulb exposing a camera negative with a peak density of 2.08 in contact with Azo. The times at a 16 1/2 inch height from the material was 15 seconds. My height from negative to paper in the enlarger for an 8X10 enlargement is 26 1/2 inches and for an 11X14 the distance increases to a height of 33 inches.

I realize that I will have some loss through the enlarger lens.

Now I have a choice of either fabricating a new lamp housing using diffusion lamp utilizing 150 watts of BLB (diffusion) or to build a new lamp housing using 400 Watts of BLB (condensor). I would prefer to use condensors. The higher wattage requires a HID ballast and it has a warm up period of some minutes. This would require the use of a shutter. I have a Packard that would work if I removed the pneumatic actuator and replaced it with a small low voltage electrical solonoid.

My concern is that since the Packard would probably need to be front mounted on the enlarger lens it may induce vibration from the actuating force.

Has anyone had experience with enlargers that utilized a shutter?

I would appreciate any feedback and guidance that others may offer.

Thanks.

[Armin Seeholzer]

Hi Don

I use an LPL 4551 enlarger with a colorhead for enlargements from 4x5 to 8x10, on AZO. AZO is blue sensitive so give him "the blues"! Till now I used a 200 watt cold mirror lamp and put a bit of blue in and I got times from 1-3 minutes at f8. Now I changed for a 250 watt lamp but had not time to test it! Preflash the paper will I also do in my next tests! Good light!

[Mark Sampson]

My idea- tried with other contact-speed materials, not Azo- was to mount a Dyna-lite flash head in place of the 4x5 Omega condenser head. compose and focus with the 250w modeling lamp, and expose with a 2000 w/s 'pop' or two. I admit that it would be difficult to dodge and burn this way, but perhaps a workaround could be devised.

[Michael Mutmansky]

Don,

We haven't discussed this issue yet, but the 400 watt BLB lamp that you mention is probably a 'normal' mercury vapor (or metal halide) lamp that has a visible light filter (called Wood's glass) coating on the outer bulb. If this is the case, there may not be any additional UV light generated by the lamp than a normal mercury vapor (or metal halide) lamp.

Regardless, I think that the condensors are going to absorb so much UV that it may be difficult to get a reasonable exposure out of the lamp. Placing that much glass (even if it is relatively UV transparent) is going to result in significant losses for sure. That's part of the reason that I think the diffusion approach is the better way to go.

As for shutters, I suspect that the exposures will be long enough that the vibration won't be much of an issue. Besides, those 138's are pretty beefy. Bolt the thing to the wall like it's meant to be, and I doubt it'll move around much at all. Mine is as solid as can be when the top of the column is fixed to the wall properly.

Another option for the shutter would be to pull the shutter out of an old Speed Graphic to use. If you make the head similar to the normal 138 heads, the opening at the heat glass is definately small enough to use a focal plane shutter like that.

One last thought. You might want to make the UV lamp run continuously, and use another lamp for focus and composition, to avoid working with UV too much. If you do that, you could use a similar arrangement as the normal 138 heads (with the mirror), and place the UV lamp (or the focus lamp) to the back. Then, make the mirror be the shutter, and place it on a swivel, which will swing to close the UV light source off, and open a path for the other light to pass through from above. It would work similar to a reflex mirror.

If you do go the route of a mercury or MH lamp, you will probably get a more efficient light source if you use a reprographic lamp rather than the BLB.

---Michael

[william linne]

There was an ad placed by and enlarger company, Durst-USA, I believe in View Camera magazine a couple of years back. A gentleman had contracted them to build an enlarger head to do exactly what you are trying to do, enlarge onto Azo. It had been done, but at some expense. It seems a big problem was keeping the head cool. Maybe someone out there with a back catalog of View Cameras can help you out. I seem to remember that they went into some detail about what had been done to the enlarger.

[Rob Tucher]

As for the shutter, I mount it underneath without attaching it to the enlarger. Then there is no concern about vibration. I use a light stand and Bogen scrim clamp and arm and just position it right under the lens of the enlarger. It works fine this way and no vibration can be translated to the enlarger.

Getting the proper color temperature and UV light output through an enlarger while regulating the intendant heat build-up has always been the problem with enlarging on Azo. I've heard of someone who has addressed this and is working on an invention that circumvents the downfalls but I don't know the approach. I've been messing with it for a long time and haven't found the perfect solution but I have been able to enlarge on the stuff. Long times are always the result. The glass of the lens is even a UV filter.

[Don Wilkes]

William:

The ad you remember appeared in the Jul/Aug 2002 Issue of View Camera, on p. 47. At the time, the company was in the process of changing its name from World Images Inc.

There isn't all that much detail about the head, but they do give a contact for the enlarger's owner. Here's the paragraph in question:

Dr. John Zdral is an opthamologist living and working in Yorba Linda. John is using a Durst L:1840 with a 10x10" Durst Condenser head for his creative landscape pictures. The particular Condenser head John is using is equipped with a special 5000 watt lamp. It is a fully-adjustable and stabilized [sic] The lamp output can be set step-less from 0-100%. The lamp is equipped with a reflector, designed by Durts-Pro-USA, Inc., that not only doubles the light-output, but also facilitates the electronic controlled cooling, with a minimum of noise. You can contact John via jzdral@aol.com

[Michael A.Smith]

The enlarging light source that I have been talking about for over a year is finally almost ready. I received word yesterday that in three weeks it will be going out to a few people for testing.

This light is cool and enlarging times are reasonable. I hope to be able to tell the whole story soon; It is not that I am holding back. I don't know all of it. I do know that the inventor had to design and patent a bulb that would be bright enough and would cover evenly. I believe the cost of this unit, which should fit any enlarger, will be comparable to the cost of a cold-light head, not in the many thousands of dollars like the Durst setup costs.

This forthcoming light is one of the reasons Kodak is continuing to keep Azo in production. The anticipation is that it could open up Azo to many more users. At my request, Kodak even agreed to make Azo in standard sizes for enlarging--11x14 and 16x20 as well as the existing 20x24 and 8x10 if it appears that demand will be sufficient. I don't expect this to happen anytime soon. A number of these light sources will have to be sold first, but if it does what it is supposed to (and I have seen the inventor's enlargements; so it looks as if it may) and people buy it the way they bought cold light heads, the long-term survival of Azo will be assured. We'll see.

[Donald Miller]

Michael, When you say that this light source will work with all enlargers, are you indicating that this will work with 5X7 and 8X10 enlarging equipment without a modification to the basic design of this equipment?

[Michael A.Smith]

That I am not sure of. I'm really not sure how the housings will work.

Will check.