Advantages and history AZO / silver chloride paper?

[B&Wpositive]

I'm young enough that I don't know the history behind AZO paper. How does it differ from your average silver gelatin paper? What are its advantages?

Why is it so legendary and what's the history behind it?

Who used / uses it?

What does "AZO" stand for or mean?

Which came first in the history of the photographic process -- AZO or "standard" silver gelatin paper? Was AZO the standard by which all others were compared, much like Tri-X for black and white film or Kodachrome for color film?

Now that someone is making an AZO-type silver chloride paper again, I'm also curious how common it is to find people using it. I hear that it's the ultimate black and white silver paper and has a better tonal depth than standard silver paper.

Can the average non-photographer tell the difference between an AZO print and a print made on standard silver paper?

Am I right that a well-printed AZO can command a higher price in the art market than a standard silver gelatin print?

Thanks!

 

[ic-racer]

Here is some stuff to read: http://www.michaelandpaula.com/mp/Azo_Writings.html

 

[PHOTOTONE]

Azo was a contact printing paper, much much slower than the enlarging papers now available. It also had a tonal curve that worked better with vigorous negatives developed for contact printing work.

 

[Photo Engineer]

It cannot be used for enlargements and was therefore the paper of choice for LF and ULF camera owners. It has no special tone scale when measured using a standard densitometer. In fact, sensitometrically, it is lower in Dmax and shorter in tone scale than most other papers in direct comparisons of data.

Many people swear by it, and others can see no difference between it and other papers. Some claim that they can see the deficiencies that I pointed out above. Some also claim that the color of the image is not up to par, but that depends on the developer used.

It seems to me, after talking to the experts that a photo print is sold on the merit of the image content and overall quality both. You cannot command a high price for a poor print regardless of the paper used.

As for Azo itself, it is a Silver Chloride paper with some Iodide in it. I have posted a formula for it here elsewhere. The paper once came in 19 surfaces on SW and DW baryta paper. They have samples of these at George Eastman House for anyone to see by appointment. They are not on display.

The paper is sensitive to UV and short visible (Blue) light and is often printed with a UV light source.

Kodak stopped making it before they ceased production of their other B&W papers due to lack of sales and the difficulty in handling baryta and single weight stock.

PE

 

[David Brown]

Many people swear by it, and others can see no difference between it and other papers.

No, no!!! It's magic! :rolleyes:

 

[David A. Goldfarb]

The main attraction of Azo for me is that it can handle a negative with more range than most enlarging papers, so an Azo print with a negative targeted to Azo can have more detail than a print with a negative targeted to most enlarging papers. It also responds well to amidol, which can give deeper blacks than other developers and works well with water bath technique for contrast control.

These things have been discussed at great length here, if you try a search on "azo," and take a look at the articles and threads on the Azo forum mentioned above at www.michaelandpaula.com.

 

[removed account4]

before M+P brought azo paper into a cult like status
it was used as a proofing paper by many ( contact sheets) - it was also one of those papers that drug stores used
to make contact prints of film in the days when people brought their film to the drug store
to have it processed and printed ... older cameras and lenses and their crazy contrast and tonality
worked perfectly with azo and again, the contact printer made things easy ( and still does ).

 

[jgjbowen]

Who used Azo/Silver Chloride Papers? Well, Edward Weston for one. Although Weston is reported to have used Haloid, another silver chloride paper; Azo is specifically mentioned in the Day Books. Edward's son Brett used Azo when contact printing. Michael Smith and Paula Chamlee are the current champions/promoters of Silver Chloride papers. Ansel Adams used silver chloride papers for his contact prints. I'd be willing to bet that most of the famous photographers of the 30's, 40's, 50's and perhaps 60's printed on Azo or another silver chloride paper.

So what are the benefits of Azo/silver chloride papers?

1) These papers seem to last almost forever. They don't need to be refrigerated/frozen to have a shelf life of over 40 years. Azo stands up very well to the aging process. If you contact print, don't want to mess with "alternative processes" and want to stock up on a paper that you won't have to throw away after 5 years then silver chloride papers are the way to go.

2) Print Color - The color of the print can be varied by using different developers, varying the amount of Kbr in Michael Smith's Amidol formula and of course by toning the prints. Azo is capable of delivering a wide range of print colors.

3) Contrast control via Amidol and a waterbath. This technique is easy to master and priceless.

4) Long tonal scale. While every paper will deliver black and white, Azo seems to do a better job of delivering the grays. If you haven't worked with Azo, that statement may seem a bit obsurd. While some of the alternative processes, most notably Platinum, will do an even better job (and Michael Smith may want to argue over this point) Azo probably does as good of a job as any other commercially available paper.

5) Ease of use. Those of us that print on silver chloride papers will tell you that the process is much EASIER than dealing with enlarging papers. By easier, I mean that it takes less time to arrive at the final print. Why? Because Azo needs less dodging/burning than enlarging papers. Why? See #4 above.

6) The Azo forum. There is a wealth of knowledge available on the Azo forum. I found the forum to be VERY, VERY helpful when starting out doing contact prints. Not that I've looked, but I've never run across the (insert your favorite paper here) forum.

So what's all the fuss about, well the only way to know for yourself is to pick up some Azo when it shows up on Ebay, Apug or the Large Format Forum or pick up some Lodima from Michael Smith www.michaelandpaula.com And I don't mean a 25 sheet starter pack. It takes a bit of testing and some time working with a paper to understand it's nuances. I contact print mostly 8x10 and I know it took me about a year and at least 500 sheets to get the feel of what the paper was capable of. Oh yeah, and get yourself some amidol as well!

I think some of the best photographic advice I've ever received was to STANDARDIZE. One film, one film developer, one paper, one paper developer. Only after you have become very well versed on how those products perform should you consider deviating. For all the reasons listed above, I couldn't imagine a better paper/developer combination than Azo/Amidol.

This is just one person's opinion and as with all things related to analog photography, YMMV

So, now I'm off to the darkroom having just returned from a photography trip, I have a batch of negatives to proof on Azo....

 

[Photo Engineer]

Well, as evidenced by Michael Smith's comments during development of the Lodima paper, it is clear that an Azo type paper does NOT have to keep well nor have a long tone scale. I believe that Michael rejected several prototypes for failing in just these areas. And, the Lodima we have now is not more than a year old, so long term keeping has not been determined nor proven. I'm not casting any doubt that it will, I'm just saying that it does not have to keep well and this property is not proven yet. Thats about it.

As for Amidol itself, this is a special order batch IIRC, and every future batch will probably have to be special order or users will have to fall back on other developer formulas. The water bath to adjust contrast can be used with other papers as well, but has not been used much.

And, the old timers used a variety of contact papers because that was all they had to make contact pints on. I used Velox, Azo and Velite for contact printing and there was also Lupex from Agfa and a few others that I cannot recall offhand. I can say that we all used these types of papers out of (in many cases) nothing more than necessity. Also, early on, enlargers were expensive and hard to get due to the fact that most everyone used ULF or LF cameras. The MF camera was also in use, but used (guess what?) contact papers such as Velox for making prints. They came in 3x4" sizes or thereabouts with pretty deckled edges or rounded corners and sometimes with striped borders.

I am neither for nor against Azo or Azo type papers. To me, it is another paper, for a specific purpose. There are those that are fanatical about it. Others that are ho-hum, and others that will not touch it. I suspect you will hear from a full range of them here.

BTW, if any of you claim that I am negative, remember that I have spent a good portion of my life the last few years re-creating Azo paper for your benefit. I am merely being a realist, and helping you all achieve your dreams just as Michael Smith has done.

PE

 

[David A. Goldfarb]

Regarding amidol, Azo and waterbath, I would say that waterbath control is more effective with amidol than with other developers, and that not all papers respond in interesting ways to amidol. Sandy King has shown, for instance, that Ansco 130 can give virtually the same tonal scale with Azo as amidol, but a water bath isn't as effective with Ansco 130 and Azo as it is with amidol and Azo, so I often use Ansco 130 with Azo or Lodima when I'm not using a water bath to control contrast, but will mix up a batch of amidol when I know I'll need an intermediate contrast grade. Efke Emaks is another paper that responds well to amidol and waterbath control.

More modern papers like Ilford MGIV FB don't necessarily do anything interesting in amidol, so it's not worth dealing with amidol to use them.

Steve Anchell's theory about this was that it had something to do with pre-hardening in more modern style emulsions that made them less responsive to developer controls like waterbath or two-bath developers, autotoning developers and such.

 

[Photo Engineer]

David;

A very balanced summary with much more detail than I could give.

I don't believe that prehardening is the answer to the question though. If that were true there would be more responsive papers than the Efke Emaks. At least that is my opinion. Also, it would have been more true years ago when few papers had the strong hardeners that are used today by Ilford. So, I think that we can throw out Steve's theory or treat it as such, a theory or maybe a hypothesis only until proven somehow.

PE

 

[sepiareverb]

....the difficulty in handling baryta and single weight stock.

Do you know more about this end of things? I quite miss my SW papers, I always did contacts on AZO or Polyfiber SW, when it went away I switched to RC, but much prefer SW.

 

[Ian Grant]

Modern papers are less responsive to development controls mainly due to changes in the emulsions particularly the removal of Cadmium from many papers, even Kodak used Cadmium until they stopped making Ektalure. Steve's theory happens to coincide time-wise with the phase out of certain chemicals, & subsequent reformulations.

Every company made Azo type papers at one time, they were once the main stream papers, and as Ron (PE) says available in a wide range of surfaces, tints etc.

I made my first prints, by enlargement on Velox (I think, aged 9 or 10) which I'd been mis-sold, these papers can be used for enlargements but without a special light source times are excessively long

Ian

 

[Photo Engineer]

Do you know more about this end of things? I quite miss my SW papers, I always did contacts on AZO or Polyfiber SW, when it went away I switched to RC, but much prefer SW.

Coating on SW FB paper is like coating on wet tissue paper!

In addition, any FB paper creates quite a bit of dust which must be controlled or removed continuously. This makes it difficult to make high quality, defect free coatings at a good price.

RC in heavy weight pretty much solves these problems.

PE

 

[David A. Goldfarb]

I'm not sure about Anchell's "hard emulsion/soft emulsion" theory either, and cadmium papers like Ektalure were fantastic, but I don't think cadmium is the explanation either, since latter-day versions of Azo and Emaks don't have cadmium.

I also remember making some of my first enlargements on Velox. As a kid, after I'd had a little experience in a darkroom that a teacher had set up in our elementary school, I'd gotten this darkroom kit, which came with a 25-pack of 4x5" Velox, a terrible 35mm developing tank with a thick flat thermometer that was used to agitate the reel in the tank, a few Kodak Tri-Chem Packs, a set of 4x5" colored plastic trays, a red safelight bulb, and what must have been the enlarger equivalent of a Holga. It was a plastic horizontal enlarger with a plastic lens mounted on a barrel that could slide back and forth to focus, and there were three slots that could hold a sheet of 4x5" paper.

 

[Photo Engineer]

Well, Azo never contained Cadmium AFAIK. So that does not seem to be the difference. It also did not contain many of the new organics that replaced Cadmium.

David, I had that same kit but the contact printing version with a gray spackle cube that was the contact printer. It had a small light bulb in it and the light went on when you closed the lid. I still have the flat thermometer here somewhere, but being worried about breaking it, I got a new tank that used a plastic stick to do the turning.

PE

 

[jgjbowen]

As for Amidol itself, this is a special order batch IIRC, and every future batch will probably have to be special order or users will have to fall back on other developer formulas.

PE

Yes, there was a large special order of Amidol imported from China a few years ago. However, Artcraft and perhaps other vendors, still import Amidol from the UK. I just purchased a few lbs of "English" amidol from Artcraft about two months ago.

 

[sepiareverb]

Coating on SW FB paper is like coating on wet tissue paper!

As I suspected. Alas. Hadn't thought about the dust, but that makes sense too.

Thanks for the info.

 

[Mahler_one]

The main attraction of Azo for me is that it can handle a negative with more range than most enlarging papers, so an Azo print with a negative targeted to Azo can have more detail than a print with a negative targeted to most enlarging papers. It also responds well to amidol, which can give deeper blacks than other developers and works well with water bath technique for contrast control.

These things have been discussed at great length here, if you try a search on "azo," and take a look at the articles and threads on the Azo forum mentioned above at www.michaelandpaula.com.

I believe David is correct....indeed, on the site noted there is a very excellent article with sensitometric objective evidence showing that the "range" of Azo paper is "longer" than other papers, especially when Amidol and water contrast development is used.

http://www.michaelandpaula.com/mp/DJ_curves_article.htm

 

[doughowk]

A nice feature of AZO/Lodima papers is the ease of pre-flashing to achieve in-between grades. I use a Bessler audible timer to get flashing times in 1/10 second intervals. I can then use my favorite developer, Ansco 130, without having to resort to water baths.
As far as advantages of AZO/Lodima, I like a remark by Paula Chamlee - its easy to get good blacks and whites but what is difficult is the greys - and that is where AZO/Lodima shines.

 

[Photo Engineer]

Some curves

Here are the curves of Azo grade 2 and 3 and the Kodabromide family of papers. The third curve is a normal grade 2 enlarging paper taken from a color example, but representative nonetheless.

The rightmost curve is a comparison of my grade 2 Azo type, Azo grade 2, and the Azo types with higher contrasts. The black curve is the Azo, grade 2 check.

All of these were processed in Dektol 1:3 and were repeated with Liquidol 1:9 with virtually identical results. It shows the lower dmax of a typical Azo type emulsion coupled with the softer toe which is not necessarily dependant on developer. The use of a water bath does help, but I often used water baths on papers when I was learning to print, as it was a common method of contrast control. IDK how much better Azo responds to this, but I suspect that being an old type emulson, the response to a water bath has been pretty much designed out of current papers to give more repeatable results.

PE

 

[Michael A. Smith]

Will try to post a quick answer. More later. Am in the Seoul Airport en route from China, where Paula and I have been printing two new books--one of which is ours.

BTW, the next Brett Weston books were printed a month ago in Belgium.

Azo and Amidol: Water bath works best with Amidol because Amidol is the most active of all known developers.

Long scale and Dmax.

For some reason, silver chloride papers do not develop well in Dektol. I will bet anyone that silver chloride papers have a higher Dmax than any current enlarging paper. Also, that they have a longer scale. Ron Mowrey is an expert to be sure, but I wonder which Azo he has tested. Over the years, Azo varied greatly. Test Azo from the 1970s to make an accurate test.

More later. Too rushed now. Will try to answer some of the original questions later. Suggest writer of those questions see my artiucles on Azo at www.michaerlandpaula.com under "Wrritings" or under "Azo."

Ciao,

Michael A. Smith

 

[Ian Grant]

For some reason, silver chloride papers do not develop well in Dektol. I will bet anyone that silver chloride papers have a higher Dmax than any current enlarging paper. Also, that they have a longer scale. Ron Mowrey is an expert to be sure, but I wonder which Azo he has tested. Over the years, Azo varied greatly. Test Azo from the 1970s to make an accurate test.
Michael A. Smith

Dektol/D72 has too high a bromide level, usually MQ developers for Contact papers contain bout a half or less bromide in comparison.

Ian

 

[David A. Goldfarb]

I think the reason that amidol works so well with waterbath control is its unusual property of development from the bottom up, rather than from the surface down. One explanation for this that I've read--and I'm interested to hear other possible explanations from the chemists--might be that the pH of the developer changes as it is absorbed into the emulsion layer so that development doesn't usually begin until it's soaked through to the bottom. Whatever the cause, it means that when you move a print from the amidol tray to the water bath, there is less concern about washing the developer off the surface of the print, because development is still happening below the surface.

My usual waterbath procedure is to develop in amidol until the image begins to emerge, transfer to the water bath, and allow it to sit for twice the emergence time, and that's usually enough for the print to develop fully. Sometimes I may move it back to the amidol tray for another round, if the shadows don't seem dark enough.

 

[Photo Engineer]

I agree with all that Amidol works with Azo and I agree as to its activity, especially on the acid side as well as when basic. My comments center on why it does not work with other papers. All is not clear on this.

As for Azo, just look at some paper curves to see that Azo usually peaks at 2.0 density or less, while other papers can continue to 2.2 or 2.4. I have seen some Agfa papers with their special surfaces reach 3.0. So, I cannot agree that Azo has more black or darker black. What it does have is a soft shoulder which allows more detail to be seen as one approaches the black that you do have. Therefore you have more shadow detail. For an understanding of this, see my curves above or better yet see the curves on the M&P web site.

As for bromide affecting Azo (or chloride) papers in general, this is a moot pont as Kodak ran all papers in a standard release test of Dektol 1:2. Azo was "designed" to work with Dektol in that sense, and many modern papers are high chloride and are not adversely affected by Dektol when diluted properly. In fact, the formula for the Amidol developer by M&P uses Bromide. So, I discount the Bromide effect.

I would like to add that the Dmax is so dependant on surface reflectivity (and drying conditions therefore) that what I say or Michael says about Dmax may both be right and wrong at the same time depending on drying and the paper sample. So, on that we can both agree and disagree at the same time and still both be right.

PE