Enlarging on Azo?

[rick_olivier]

Does anyone know of the mysterious details about actually

ENLARGING on Kodak Azo? M. Smith and P. Chamlee will be

unveiling this in the near future, but I'm looking for a sneak

preview. thanks Rick Olivier

[john_cook1]

The Kodak contact printers I used in the old days to make 8x10 contact prints were much brighter that modern enlargers. Exposing an 8x10 print from a 35mm negative will take forever. You had better watch for safelight fog with the paper sitting out that long.

[michael_wellman]

Check out the July/August 2002 issue of View Camera on p47. The ad for Durst enlargers talks about using a 5K watt condenser head to enlarge on Azo. The ad doesn't talk about the exposure time required, but I recall seeing a note he posted on Michael's and Paula's web page and I think he mentioned normal exposure time were well under a minute. The ad does list an email address for him.

 

This may not be the same person who Michael Smith has been reffering to about creating a light source strong enough for Azo with an enlarger, but it does show that it can be done.

[geoffrey_james]

If you could get a powerful light source like pulse zenon, it would work. I used to use Azo a lot for contact printing panoramic negatives, but gave it up for a vaiety of reasons. I certainly don't want to get hooked on a product that isn't manufctured any more. And I find I can get better prints out of the warm tone Forte.

[j._marten]

Azo is still manufactured.... great stuff!

[wickedmartini]

I have experimented with printing on Azo and the results can be very interesting if not unique. I have an old 23CII XL. I just opened up the lens a bit and the exposures were not too horribly long. It can have a very rich look to it and I found that I like the way it reacts to various toners as well.

 

Have fun! It's worth a shot...

 

Michael D. D'Avignon

[michael_a._smith1]

The fellow who has invented a light source for Azo--one that will

work, with the proper adapter, on all enlargers, is not the same

fellow with the 5,000 Watt bulb. (By the way, where was that

article published--I never did see it.) This will be a cool bulb, not

a hot one. We'd reveal all about it now, but it is not perfected yet.

A special bulb has to be made in the right configuration to give

even illumination. And manufacturing a new light bulb is not

easy, nor, I understand, inexpensive.

 

And to the fellow who said that Azo is defunct: as someone else

responded, it is not. Full details about current sizes and

availability can be found at www.michaelandpaula.com.

 

Michael A. Smith

[walter_glover]

Michael,

 

After all the advice you have so freely given it is a joy to return the

compliment, if only in a small way:

 

View Camera � July / August 2002 � Page 47

 

Cheers,

 

Walter Glover

[jens_jensen]

Enlarging on Kodak AZO paper is a challenge due to the very low speed of the AZO paper. As is evident from Kodak�s web page, covering the issue of AZO paper, this paper is entirely intended for contact printing in a contact printer using incandescent lamps. Kodak actually makes it a point to underline the fact that this paper is not intended for enlarging. The fact Kodak make this remark is entirely due to the speed of the paper. No other qualities prevents the paper from being used for enlarging.

Kodak points out that AZO paper is �blue sensitive�, which translated into spectral terms means that it�s spectral sensitivity is in the area 350nm to 400nm � being most sensitive in the high end. (More details at http://www.durst-pro-usa.com/explantion_light.htm)

The paper being blue sensitive is also the reason for it�s very slow speed (ISO speed P4). Incandescent lamps produce least light in the blue spectrum thus making exposure to incandescent lamps extremely ineffective = slow speed.

A tungsten or tungsten halogen lamp converts only approx. 8% of the energy consumed into visible light ( 380-780nm). Of these 8% only the smallest fraction is radiation emitted in the blue area � 350 to 400nm. If we decide to name the 8% turned into visible light �100% usable light� then only approx. 2% of the �100% usable light� is in the blue area. Or with other words, only 2% of the light you see emitted by a given lamp is seen by the AZO paper.

So it is understandable that the AZO paper is slow when rated against an incandescent light source.

When considering a light source for enlarging on AZO paper it is therefore very important to consider both the quantitive properties and the spectral qualities of the light source.

Some Metal Halogen lamps and some fluorescent tubes emit up to 5x more light (10% of the total emission) in the blue area.

Based on numerous tests I have found that it is very hard, if not impossible, to obtain high concentrations of light from a Fluorescent lamp on a relative small area, none of the tubes that are commercially available can compete in output (Lux) with a Halogen lamp. 2% of the visible output from a 5000 Watt halogen lamp is under any circumstances �more� than 10% of a 100 or 200 watt fluorescent tube, which physical size also is far greater than any halogen lamp, even a 5000 watt halogen lamp is smaller in physical size than a 100-200 watt Fluorescent tube.

There is no doubt that a bank of fluorescent tubes will be a more efficient light source for contact printing on AZO paper than most any incandescent lamp of the same wattage. A bank of fluorescent lamps will be the best light source for contact printing as long as there is no need for local dodging and burning by turning on and/or off single lamps in a series of incandescent lamps.

Still a 1000 watt or even a 500 watt bare incandescent lamp will print even faster when contact printing on AZO.

I have not even considered the metal halogen lamp in this context due to its extensive warm up period which would require the lamp to be on constantly and the enlarging lens to be outfitted with a shutter. And also due to the bulkiness and price of Metal Halogen lamps. I will appreciate any comments or ideas on how to overcome the problems involved in using a Metal halogen lamp for AZO printing.

When I examine the above findings together with the knowledge that I have obtained by comparing diffused light sources to Specular light sources (Condenser) I have concluded that the best possible compromise, when enlarging on AZO paper, is a condenser head with a powerful diffused tungsten halogen lamp. (I have posted my comparison of diffused light sources and Specular light sources on http://216.87.164.59/artcon.htm )

To my knowledge no other lamp type exists that can both be concentrated on small areas (35mm) and at the same time emit enough useable light to produce a print with a reasonable exposure time which I consider to be less than 5 minutes for a 20x24� print from any size negative.

It is possible that a lamp can be designed that will be more effective than a generally available tungsten halogen lamp. However with knowledge of the cost involved in producing much less complicated lamps (100watt � 24Volt point light lamps) I very seriously doubt that such a venture is economically possible due to the size of the market interested in enlarging on AZO paper. We are not talking about thousands of orders for such a lamp source, rather dozens, and thousands are necessary to produce a lamp with special spectral properties at a reasonable cost.

Based on my previous conclusion, and the size of the market interested in AZO enlarging, I have designed a 1000 watt and a 5000 watt Durst condenser head perfectly suited for printing on AZO.

The fact that a condenser head produce a print with a higher contrast than a diffused light source would, from the same negative, the Condenser head actually work in our favor since it will allow us to expose and develop negatives for enlarging on AZO paper LESS than we normally would for contact printing and will therefore in it self reduce the exposure time.

Since the world rarely is perfect there are also drawbacks to using a condenser head for enlarging on AZO paper. Existing negatives originally produced for contact printing on AZO paper tend to produce rather contrasty and grainy prints when enlarged with a condenser head.

However if you have a stock of normally exposed and normally developed negatives you are ready to start printing on AZO, your normal negatives will print beautifully with an AZO Condenser head. Whether you choose a 1000 watt type or a 5000 watt type is merely a question of temperament and print size. Kodak does stock AZO in 20x24�. There are a 2-stop difference in speed between a 1000 and a 5000 watt AZO Condenser head.

 

You are welcome to contact my self for further discussions, email durst-pro-usa@msn.com or simply call 503 846 1492. If you are interested in user details such as actual exposure times and practical details I can suggest to contact Dr. Zdral at jlzdral@msn.com. Or lock on to our webpage DURST-PRO-USA.COM for more technical details.

 

Good luck

 

Jens J Jensen.

 

Kodaks azo site: http://www.kodak.com/global/en/professional/support/techPubs/g10/g10.jhtml#ISO%20Paper%20Speed%20and%20Range

 

[tim_atherton2]

"Azo is still manufactured.... great stuff!"

 

Unfortunatley, not in all the grades it needs to be

[armin_seeholzer]

To Jens Jensen or sombody els who knows!

1. would it not be possible with a color head and but the blue filter in to make enlargements on Azo?

2. Is there in Europe somewhere a distributer of thad paper?

 

Thanks