Enlarging on Azo and Platinum

[David Hall]

I like the idea of using the strobe. When I first got Azo and realized that an enarger light wouldn't do it, I almost used the modeling light from my softbox...250w, variable, etc. Then I got a 250w enlarger bulb, plugged it into a regular socket, and it works like a charm. It is very thickly coated white so the light is even; no hot spots.

As for using a strobe...does the volume and duration of the pulse ever change? Seems like it would be hard to have repeatable printing if the light changed on you.

dgh

 

[Donald Miller]

Actually strobe output is very repeatable since it relies on the charge in a bank of capacitors or that portion of the bank of a bank of capacitors that you utilize in a variable output situation. It does not rely or is it directly affected by input voltage to the power supply. Usually a capacitor will serve several functions, depending upon the circuit design.

In the case of most common, continual output, pulsed Xenon (apart from photographic strobes) capacitors would serve to store voltage to contribute to supply voltage in the event of a voltage drop. So in that situation they would serve as a voltage stabilization means.

However in photographic strobes where one has a single discharge at a time capacitors store DC voltage, (since they will only store DC and will pass AC) they store voltage and then are triggered to discharge to the Xenon tube. The way that DC voltage is arranged for is that AC voltage is rectified through bridge rectifiers or a diode bridge network. The reason the photographic strobe is designed this way is that this provides the control of the time factor in the equation of quantity of time and measure of light equally exposure.

 

[Ed Sukach]

</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (dnmilikan @ Feb 7 2003, 01:23 PM)</td></tr><tr><td id='QUOTE'>Ed, the site is down the page and is listed with a URL of Durst Pro Usa. If you fail to locate it get back with me and I will get the actual URL for you. Good luck.
</td></tr></table><span class='postcolor'>
I finally found it - it was sorrt of hidden behind the title of "A paper: Something About Bill Clinton and Light Heads".

Some good basic optical "truths" here - although written a little too complicated - "overworked" ... and rather obviously predjudiced toward "Condenser" (or as it states, properly "Collimated") light sources - especially the "Durst" ones.
This guy sdoesn't care much for "Cold" light heads, with multiple "tubes".

I work with an Omega D5500 - wth the dichroic head - classified as a "Diffusion" light source - but that is not entirely true. Properly it is somewhat of a "hybrid", as the built-in reflector on the halogen bulb collimates the light.

 

[Donald Miller]

Ed. I agree, I think that I need to cut down on the meds so that I can see the lights and hear the music again. Maybe then I can come up with some new and original inspiration. Oh the wonders of better living through chemistry.

 

[avandesande]

The only problem with strobes is that you will see hard edges when you burn and dodge. Most tubes cannot go anywhere near the 20hz or so that would avoid this problem. You will need a bank of tubes that are fired in order.... It gets complicated fast.

 

[Donald Miller]

Yes, Aaron, that is true. I would like to find a soft and easy way to accomplish this for a variety of reasons. Unfortunately, I haven't found it to be so. Thanks for sharing the hard edge issue...I was not aware of that.

 

[David Hall]

Back to the printing on Azo for a minute...

Someone earlier said that the paper is UV sensitive. Does that mean you could get one of those plant growing lights at the hardware store and have some luck? In other words, would you need a lot less wattage if you used light that was at exactly the right wavelength for the paper?

dgh

 

[Donald Miller]

That is a good question, David.

By virtue of the published spectral sensitivity data on the Kodak site and in speaking with their technical representative last week, I was told that Azo is only sensitive to UV, since the chart shows no measurable sensitivity above 460 nm.

The metal halide, or mercury arc lamps that are being used emit only 20% appr. of their output in the UV spectrum. The remaining 80% is divided with 60% being in the visible spectrum and appr. 20% being IR. That would mean that 80% of the light and heat output from these sources are wasted.

So it would seem that a purely UV emitting source would be most efficient. There are 3 regions of UV classification with the A region being the one that we are concerned with. So if you decide to pursue this, look for something in either the frequency range that Kodak publishes or a source that is advertised as being an A region UV emitter.

Good luck if you decide to pursue this and I would appreciate your feedback on your efforts

Regards,
Donald Miller

 

[glbeas]

</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (avandesande @ Feb 8 2003, 05:45 PM)</td></tr><tr><td id='QUOTE'> The only problem with strobes is that you will see hard edges when you burn and dodge. Most tubes cannot go anywhere near the 20hz or so that would avoid this problem. You will need a bank of tubes that are fired in order.... It gets complicated fast. </td></tr></table><span class='postcolor'>
I've used the Minolta 45A head with the strobe tubes and I can burn and dodge with it without too much difficulty. You get the softening effect from the edge of the dodge tool being fairly close to the lens.
For a contact printer this softening can be accomplished with a diffuser in front of the strobes reflector so the light source is much less of a point. The same principles apply that you would use in setting up soft light with a studio strobe.

 

[Donald Miller]

This is an update to those who have an interest in enlarging on Azo paper. I spoke with an engineer at Aristo Grid Lamp Products this morning about enlarging on Azo and he is to mail a test lamp to me either tomorrow or as late as next Tuesday. This will be a test of the spectral response of Azo to a lamp with a peak emission in the 360 nm range. I will then wire it into the transformer that I have on my old D2 cold light head (no longer using it now). If the paper exposes to this spectral output the next step is to increase the intensity of the lamp so that the slow speed of Azo is addressed. It is nice to finally have something moving along in this process. I will keep making posts as to the results of the testing from time to time. If any have questions, you may email me offlist or post your questions here.

 

[David Hall]

Donald,

Not sure I understand...does this Aristo lamp approach Azo from a UV standpoint, using regular power, or a power standpoint using a cooler light?

dgh

 

[Donald Miller]

David,
Thank you for your enquiry and you posed a good question. The matter is one of the spectrum of light that is emitted. Azo exposes in the range of 350-460 nm, which is in the UV spectrum. The phosphors which are added to the tube that they manufacture can control the wave length of light that the bulb emits.

Current metal halide or mercury arc lamps, while they do emit UV, also emit 80% of their light output in the visible and IR spectrum and this is wasted energy and also causes immense heat loads that must be dealt with.

Hope that this answers your question. Good luck.

Regards,
Donald Miller

 

[David A. Goldfarb]

If the paper is sensitive to UV, and we are focusing with visible light, and most of our enlarging lenses are not designed to be apochromatic for UV, won't there be some focus shift with a system like this?

 

[Donald Miller]

David,
A very pertinent question. This matter has been addressed and the indications that I have received are that the portion of the UV spectrum that is involved here is commonly known as "type A UV" or in other terminology "near band UV". This is the portion of UV that is in the still visible purple band in the 460 nm portion. As such, it is not as prone to the effects as the other two bands (b and c) to focus shift. The amount of focus shift, if any, I have been told would be so minimal as to be inconsequential. While the transmission of UV can be affected by the enlarging lens, there are lenses that will function without going to the expense of a quartz lens specifically designed for UV transmission. The El Nikor lenses, I have been told, will work with the UV spectrum which is involved. Thanks for your question and I hope that I have adequately answered your questions.

Best regards,
Donald Miller

 

[lee]

I know that Azo is a nice paper but I question the expense of engineering something that will allow for enlarging on this paper. It is contact paper. I would rather buy a bigger camera and make contact prints on Azo. Just me and the weird way I think. Isn't it sorta like finding an answer and then figuring out the question? I don't know you tell me.


lee\c

 

[Donald Miller]

Lee,
You raise a valid point and certainly one which must be considered. The factors which seem to be involved with this are the following, as I see them.

1. There will never be an enlargement that will duplicate the appearance of a contact print.
2. Therefore if one is attempting to achieve the greatest fidelity in the print, one will photograph using a camera which exposes the size of negative which will give the size of print wanted.
3. As print size increases above 8X10 then we enter the realm of ultra large format equipment.
4. Ultra large format equipment is expensive and it is heavy. It also suffers from additional considerations. Among those are that as the diagonal of the film increases so does normal lens focal length. As focal length increases depth of field decreases. To gain depth of field, one will need to stop down smaller, so considerations of movement in leaves, grass and natural objects becomes an ever increasing factor.
5. There are not a large number of people working in ultra large format for the reasons I mentioned.
6. A 4X5 contact print can be appealing but it quite honestly is too small in many cases.
7. To get a 4X5 negative to a larger size consists of one of two methods. Those being either enlarging the 4X5 negative onto paper or creating an enlarged duplicate negative to contact print with.
8. Creating duplicate enlarged negatives is time consuming and while possessing of several benefits are also possessing of several detriments.
9.The enlarging equipment coming to market for enlarging onto Azo is expensive. $5,500 for the 5X7 from Durst which is the only enlarger presently slated for that specific purpose.
10. There is a great quantity of enlarging equipment, already in user's hands, that is perfectly capable of producing enlargements onto Azo if the light source problem can be resolved.
11. While an enlargement will not duplicate a contact print, an enlargement onto Azo, if possible, will be better then an enlargement onto any other paper.

I am sure that other considerations may be involved. If you have thoughts about this, I certainly appreciate input from all. Thanks again for raising a very pertinent question.

Best regards,
Donald Miller

 

[Jorge]

I dont know if I agree with point number 1 Donald. Some of Paul Caponigro's prints are enlargements and they sure do look just as good as any contact print I have seen.
As it happens I met David in Mexico City and brought a 16x20 enlargement and his comment was the same. I do have to agree that for some reason contact prints seem "easier" to print. But enlargement can come awfully close if not as good.

Any ways I am with lee, I rather buy the 16x20 camera than spend $5000 on an enlarger.

 

[lee]

All that you say is true, Donald. Without a doubt. My experiences with Aristo Grid is that the cold light head you want is gonna be expensive. I own 2 right now. One is a older style with the older blue light grid and the other is what I use now. The Aristo VCL 4500. That one I got used at Midwest Camera Exchange and I got a deal $700. Those things are nearly $1500. I have not looked in a while. It is a great head, no doubt but it is expensive. I have a Metrox II timer that I control the head with on the Omega that is also expensive. It is a nice combo. I get too distracted to just a metronome. Plus, I like to listen to classical music when printing.

As long as I can carry a camera, I will long for something bigger in a camera. I am one of those infidels that will use enlarging paper for enlarging and contacting also. I know, I know it is blasphemy. I can live with that.

lee\c

item #3 should read, "as Negative size increases past 8x10" Picky but I knew what you meant.

#4 is an issue that must be addressed with any and all largeformats wrt, movement like in grass and the like.

#5 I use contact prints with all my camera formats 4x5, 5x7 and 8x10

Has Aristo Grid given you any estimated cost of the head after the R&D is done?
I would bet it will be in the neighborhood of 3k or 3.5k That is a WAG but I would bet it is close.

lee\c

 

[SteveGangi]

I bought my 5x7 and 8x10 for several reasons, one of which was contact printing. All considerations of how good an enlargement looks aside, Azo is a very slow paper with a long range. So, it is good for those hard to print negatives, and I do like the look of a contact print. I don't think I would pay 5000 for another enlarger, when a floodlamp, stopwatch and contact frame do the job for me. The price is too high, and where would I keep it? Now if they ever came up with a lightbulb that screws into the enlarger I already have, my tune will probably change. I admit it, I am a heretic. I have contact printed on enlarger type paper using a tiny lightbulb too. My biggest complaint was, it was too darn fast.

 

[Donald Miller]

An update on the availability of a enlarger/light source for enlarging on Azo. I received a letter and information packet from Durst Pro USA this morning. As some of you may recall, they had initially stated that they would be bringing a 5X7 enlarger to market that would be suitable for enlarging negative on Azo and Platinum. The proported release date was to be March of 2003.

They have now decided that they will not bring the UV only light source to market because in their judgement insufficient market demand exists. They have decided instead to bring out what they term the "Azo" head. This light source will be suitable for both Azo and regular graded or VC paper. This source will be marketed "later this summer".

Additionally, aside from Durst Pro, as I may or may not have shared (I can't remember, since I talk with lots of people). There is an individual that is developing and bringing to market a light source which will expose Azo and this light source is apparently adaptable to existing enlarging equipment. This light source required the manufacture of an entirely new bulb with it's emissions in the appropriate spectrum. This, according to Michael Smith, is supposed to be available to the market later this year. I have been suggested as the test for this light source, prior to release. At this point, I am taking a "wait and see" attitude on this whole matter. Mr. Zdral, the photographer who enlarges on Azo, has indicated to me that the quality of the enlargements are better then any other paper available at this time. Having contact printed on Azo I could see where that would be true.

 

[LaChou]

An unprejudiced point of view

Guys, you are tripping.
(Being a Ukrainian girl I don't fully understand the slang meaning of this verb but my intuition sais it would come right in here...)
Do you really think all this to be worth SUCH money?
Even if my carrier as a model had been successful I wouldn't ever spend so much money on an ENLARGER.
Think it my way: "I don't need NASA-level enlarger to bring me the joy of a picture appearing on a sheet of paper under red light in my bathroom".
I would spend such money on optics, may be...
There are many good B&W photographers in Russia but I even haven't HEARD about one using such an ESOTHERIC ways of obtainig a good print.
Does this tonal range really matter so much?

 

[jmdavis]

Guys, you are tripping.
(Being a Ukrainian girl I don't fully understand the slang meaning of this verb but my intuition sais it would come right in here...)
Do you really think all this to be worth SUCH money?
Even if my carrier as a model had been successful I wouldn't ever spend so much money on an ENLARGER.
Think it my way: "I don't need NASA-level enlarger to bring me the joy of a picture appearing on a sheet of paper under red light in my bathroom".
I would spend such money on optics, may be...
There are many good B&W photographers in Russia but I even haven't HEARD about one using such an ESOTHERIC ways of obtainig a good print.
Does this tonal range really matter so much?

It is interesting that several of the people who like Azo are now using or trying Slavich Unibrom (single weight) until an azo replacement is available. In terms of contact printing, I believe that there is a difference. In terms of enlarging, I am told that the difference is visible.

I did not buy one of the coldlight Azo heads, I thought about it, but then decided that a 150 watt R40 bulb worked just fine for my contact prints.

Mike

 

[donbga]

Does this tonal range really matter so much?

For those intrested in these two processes the possibility of enlarging images rather than contact printing has appeal. But as you note the high cost of a machine like the Durst certainly precludes its use by most people interested in these processes.

Better to make an enlarged negative.

 

[Alex Hawley]

Does this tonal range really matter so much?

Yeah, it does for some of us. Both tone and tonal range. I have been fooling around with various papers, ever since Azo went away, trying to determine which one comes closest to Azo. Slavich and Kentona are close, Kentona being closest. Ilford MGIV is pretty good too.

The Slavich paper is pretty good. I don't think many of us here in the USA fully appreciate it yet. I just bought some in 16x20 for trying it in the 7x17 format.

LaChou, welcome to APUG. Glad to see someone from the Ukraine here. You're right, there a many fine B&W photographers in Ukraine and Russia. Wish they were more visible here.

 

[Bob Carnie]

Don
Though I agree with most of your points and respect your opinon.I have to disagree on #11.

#11 re Azo paper being better than all other enlarging papers in my humble opinion is totally off base.
I have seen Azo and Ilford Warmtone as well as Forte in the same room , all printed by very competent artists.
The Azo prints though beautiful, did not exceed my quality expectations and many other *eyes* that I respect over the more mainstream papers in the same room.
I am not sure I will ever see better samples Azo, Ilford and the other papers that were in that room. But for sure they were of equal quality and brilliance.