Tests by Dhananjay Nayakanakuppam
The developer curves here are for the following
Defender 55-D cold tone developer (very similar to Dektol)
G262 warm tone developer at 1:1
G262 warm tone developer at 1:6
The paper was exposed to a 31-step step wedge. Chart 1 plots the print reflection densities against
the step number. Chart 2 prints print reflection densities against the transmission density of each step. The print reflection densities were read off a Macbeth densitometer - I didn't have the
calibration plaque, so I zeroed it off the base white of the paper and went from there.
These tests were done at various points in time. The Defender was done first. The Ansco130,
G262 at 1:1 and at 1:6 was done at a later point in time, and the Amidol even later. Unfortunately, the paper probably comes from three different batches as a result - I would be surprised if this
changes any of the results but figured I should mention it anyway.
The other thing I should mention is the huge range of colors I can get out of Azo - easily the most
colorful paper I've worked with. It yields tones from cold bluish all the way across to warm yellows and browns, even without the toning. Azo in 55-D (or Dektol) provides nice cold gray
blues. In G262, the tones are much warmer, in the yellow-brown range. Toning naturally can alter colors further. No other paper I've encountered was this responsive to different developers in
terms of color. I wrote up some of this stuff on the toning and sent it to Michael Smith for his Azo forum - I figure the more people we can get turned on to this paper, the better the chances of
keeping it in production. My speculation (articulated in that paper) is that the pure silver chloride makes for a much more flexible paper. Silver chloride makes for smaller grains than bromide, and
I'm surmising that is why Azo is so colorful (color is closely tied to size of the developed grain).
As regards gradation, again Azo seems very flexible, as can be seen from the curves. Other papers
do not seem as flexible. I'm guessing most modern papers are made as zero error papers i.e., processing under a wide variety of conditions can still yield identical results. Plus, of course, most
papers are bromide (or chlorobromide) emulsions made for enlargement and as such probably have other design limitations (enlarging papers will require higher speed, for e.g.). For example,
lots of papers are probably designed with roll film users in mind and have longer toes to accommodate denser highlights on those etc. And like I said, I think manufacturers want repeatable
results from a wide variety of processing - which I guess is great when one is getting one's process under control, but I'm sure it does impose other kinds of design limitations.
The Amidol formula I have invariably ended up using is the one on Michael Smith's site. I think
Amidol is a really spooky developer - highest reduction potential of any developing agent, even active in acid solution, and does the funny trick of developing from the base up (in acid solutions).
It's a diaminophenol, and is quite unlike any other developing agent. It's not sensitive to its oxidation product, which means it goes on and on - I suspect this is one of the reasons Amidol
provides the straightest D-log E curve possible for a paper. The oxidation product of Amidol is supposedly quite a good restrainer, which might be a reason Michael Smith's formula has the bromide cut way back.
Amidol also has a bit of a bad rap for dying quickly and in general, not lasting. Part of this is because traditional preservatives do a poor job of preserving Amidol (with its lust for AgX and
suicidally, for air). Citric acid seems to do the trick nicely enough. I've used Michael Smith's formula and worked over a 48 hour period, putting about 70+ prints, and it was still going at the
end of that.
Richard Henry of course did some tests and found that Amidol didn't seem to result in higher Dmax etc. That may be true but it does seem to yield superb gradation and works wonders in a water
bath - its powerful enough that you don't need to go back and forth between the developer and the water bath.
Attached are scans of prints in Defender and Amidol - the color differences alone are striking.
Differences in gradation are quite obvious in the print but I don't think they are too visible in the scan. The shadows are a little murkier in the Defender, although it holds some cloud detail with
low contrast (due to the long toe). I'm sure a water bath would have put that in the Amidol print too.
Printing with Azo
by Ed Buffaloe
I was intrigued by Michael Smith’s claim that Azo has a greater
tonal range than platinum papers. I can’t vouch for that personally, but I can say I have printed a number of my 8x10 negatives with no dodging or burning whatever, and the scale is
truly remarkable--better than any enlarging paper I have used. I like the deep blue-black color of Azo’s untoned emulsion and, even more, I love the warm purple-brown of it when toned in
selenium. The whites are crisp and clean. Azo seems to work particularly well with pyro negatives, producing superb contrast and gradation. If you work in large format, I recommend you give
this paper a try.
I used the Zone VI cold light head on my Beseler 45, as close to the paper as I could get it, with the
power turned up as high as it would go and still remain stable. My exposure times ranged from 2 to 5 minutes. Bob Herbst informs me that he uses a 100 watt soft white incandescent bulb in a 10
inch reflector about two feet above the paper. His exposure times range from 5 to 30 seconds.
I decided to try an amidol formula, since several people on the photo forums have stated that it gives good results with Azo. I chose Peckham Amidol at half strength as an economical, clean
-working solution. My developing times ranged from 3 minutes to 15 minutes. It doesn’t seem possible to overdevelop Azo. Most of my negatives seemed to do just fine on grade 2, though
there is one I’d like to try on grade 3. I may also try developing it in an undiluted amidol solution.
The gold toner I used on a few prints was 3 grams of thiocarbamide (thiourea) and 5 ml of a 1%
gold chloride solution in a liter of water. Azo tones readily in gold, though I prefer the warmth of selenium.
Azo is a very slow chloride emulsion for contact printing, and is one of the oldest papers still in
production by Kodak. But the fact is Kodak can’t sell enough to justify continuing production. Michael Smith and Paula Chamlee of MichaelandPaula.Com are trying to save this wonderful paper by becoming the premier distributors of it in the world. Please order from them.