AZO 411

[Donald Miller]

Don, everything you say squares with my understanding of the principles involved, but I have no first hand printing experience with Azo. I am encouraged that your experience matches my understanding, and also coincides with Sandy's research. I would be interested to now why Fransesco and others appear to get better results by methods that seem counter to the sensitometry of their materials.

From what I can gather, the only thing that a fuller exposure would accomplish is to move the shadow densities off the toe of the films characteristic curve. This would provide better shadow separation but this must by the nature of the materials come at a cost of compressed overall tonal scale or compressed highlight densities with most films.

 

[Alex Hawley]

I'm glad ya'll are having this discussion. Nothing for me to contribute from my 2 weeks of Azo experience, so I'll set back, read, and learn.

 

[David A. Goldfarb]

Certainly with SXX, a dense negative should give good shadow detail, since the shadows will be well off the toe, and there's plenty of scale at the top of the curve to keep good highlight detail, as long as you're not trying to increase contrast through extended development, say, two zones beyond normal. Other films may just max out in the highlights before you get that far.

I wonder, though, if another factor may be at work having to do with Azo's reciprocity characteristics or something of that nature. A denser neg might just make it easier to get to Azo's ideal exposure time, whatever that may be.

 

[Donald Miller]

Certainly with SXX, a dense negative should give good shadow detail, since the shadows will be well off the toe, and there's plenty of scale at the top of the curve to keep good highlight detail, as long as you're not trying to increase contrast through extended development, say, two zones beyond normal. Other films may just max out in the highlights before you get that far.

I wonder, though, if another factor may be at work having to do with Azo's reciprocity characteristics or something of that nature. A denser neg might just make it easier to get to Azo's ideal exposure time, whatever that may be.

The other factor that may be at play here is the characteristic curve of Azo. I read the reflection densities of my test which indicated the negative density range that Azo would accomodate but I did not plot curves for the paper. I could do that since I have all of the data. The thing that may be occuring is that the curve of the film could be interfacing with the curve of the paper in such a way that an unattractive compression may be occuring. I could certainly see that possibility with the shadows lying on the toe of the film's curve and then falling on the shoulder of the paper. That would be a recipe for flat shadows.

 

[Francesco]

It does not take long to find your own groove when it comes to contact printing on AZO. More or less density, more or less contrast, try them all with AZO is what I have done. I even switch bulbs (I use a 60w and a 200w) mid printing just to see differences if any. Rather than denisty or contrast I look for detail instead. If there is plenty of it then it will work! Check the negative on a lightbox and see if it has all the information that translates how you felt when the photograph was taken. If I like the negative then I will like it on AZO.

 

[mwtroxell]

"I started out with a 200w bulb but moved on to a 60w bulb in order "

Everyone mentions using a bare bulb with Azo. I'm working in a community college darkroom. Is there any difference between bare bulds and contact printing using a condenser enlarger as the light source?

 

[Donald Miller]

"I started out with a 200w bulb but moved on to a 60w bulb in order "

Everyone mentions using a bare bulb with Azo. I'm working in a community college darkroom. Is there any difference between bare bulds and contact printing using a condenser enlarger as the light source?

The major problem with using an enlarger for a light source to expose Azo is that the amount of light available may not be capable of producing short enough exposures. A great deal depends on the overall density of the negative. Azo by nature is a long scale paper. To utilize the full potential that the paper possesses this requires a negative that has a greater density range then a conventional negative suited for enlarging. This does lead to higher overall negative densities which in turn leads to lengthy exposure times. If I were going to use an enlarger for the light source I would remove the lens and lens board. I would bring the lamp house down to the point that the projected beam covered the printing frame or negative size and then expose under those conditions. This may be suitable to your demands and you may find that it isn't. It certainly would cost nothing to try.