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Tests by Dhananjay Nayakanakuppam
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Test details:
The developer curves here are for the following
Defender 55-D cold tone developer (very similar to Dektol)
Ansco 130
G262 warm tone developer at 1:1
G262 warm tone developer at 1:6
Amidol
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.
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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.
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