AZO?

[jnanian]

max

i think it was just a name.
like dektol is a name, metol ( or kodak's name for their metol was elon )
or selectol o r... i think azo was just a name, nothing more than that.
like kodak is just a name, cause it sounded good, and was easy to remember.

i could be wrong though...

[maxbloom]

It is catchy. I'd love to believe that's the case but I just don't believe they would use the name of an organic functional group without it having any relevance to the paper.

[ann]

i know that Brovira has a high level of bromide but it was also full of cadmium so why not call it caovira.

[maxbloom]

i know that Brovira has a high level of bromide but it was also full of cadmium so why not call it caovira.

Because cadmium was a staple of most papers for a long time. Would be like naming a paper silvira.

[ann]

and bromide is in a lot of papers, but i surrender at this time.

[Photo Engineer]

Velox, Velite and Azo were Kodak's trade names for slow gaslight or UV sensitive products that could be used under low room illumination. Azo had the best tone by far. Some early papers were stabilzed by using Sodium Azide which is explosive and hard to handle. Maybe this is where it came from. IDK.

A derivative of Sodium Azide is used today in airbags in cars to puff them up when struck hard.

Agfa produced a similar paper to Azo called Lupex. Azo and Lupex were both Chloro Iodide papers. That is, they were made with both chloride and iodide. I have argued this point before here, but it is true.

Some eastern European companies still use Sodium Azide for stabilization of emulsions. See Jim Browning's web page for a formula which uses it.

Kodabromide and Brovira were both Silver Chloro Bromide emulsions with a dash of iodide, a big slug of cadmium, some formulas had mercury and lead. They were a toxic brew depending on contrast grade and image tone. Cadmium was not used in Azo AFAIK.

Cadmium was used in the make or just before coating and was used at about 5 - 15 grams for every 108 grams of silver which was a BIG dose. Current chemicals that replace Cadmium are used at about 6 x 10^-6 grams / 108 grams of silver, so even if they are a bit on the toxic side, they are used at levels of 10,000,000 x lower or thereabouts.

Does this help?

PE

[htmlguru4242]

On the topic of Azo and what it contains,

PE, just out of interest, do you have any [relatively] specific information about Azo as to what it contained / how it was made?

[blaze-on]

Is there tri-x compound in tri-x film? or was it used for filming XXX movies?

[Photo Engineer]

Azo was a single run silver chloro iodide. It was a very simple emulsion similar to the one I posted here by Bruce Kahn, formerly at RIT. It contained a stabilzer such as Tetra aza indene, and a sensitzing dye (IIRC - it may not have). It had no Cadmium in it AFAIK, but Kodabromide and other enlarging papers did.

After the run, it had a very short digestion period and then was coated with muchochloric acid and formaldehyde hardeners. It had an overcoat applied at a second coating station. At one time, it used saponin as spreading agent, but Kodak was changing over, so I don't know if that was used in the later batches.

The Agfa version used sodium sulfite and formalin only with a sulfonic acid spreading agent (again IIRC).

Kodak Azo was coated on a tinted SW baryta support. At one time, Azo was supplied in 19 different paper surfaces. Samples are in the GEH archives and viewable by appointment.

There was once a warm tone Azo which contained ammonium salts during the run, and also copper salts. This was similar to the Agfa Lupex.

PE

[Vaughn]

Thanks, PE. Your willingness (and patience) to share info is much appreciated!

Vaughn