Some weeks ago, I started a thread on ET developers, and it didn't attract much interest, but I did get some e-mail asking for more information.
This post is intended as a continuation and update for those interested.
Imagine a mix of 2 developing agents. One is very active but used in low concentration. Its oxidation products do not decompose. Imagine another which is much less active, but reacts with the oxidation products of the first developer, and which itself has oxidation products which decompose into less active material.
An example of the latter is hydroquinone, which when oxidized forms hydroquionone monosulfonate in developer solutions. The activity ratio of HQMS to HQ is about 20:1 or larger.
So, lets assume a mix of 0.1 gram of a highly active developer and 20 g/l of a poorly active developer. But, the pair interact to regenerate the active developer.
Now, what is the result? The result is an active developer that keeps regenerating itself. What is the result for the user? Well, this type of developer has high capacity or long tray life or both. It will yield the same results for a long time allowing process uniformity when you want to print a lot of exactly the same print. It also means that when the developer begins to die off, you can recreate the original result more easily just by increasing development time.
In fact, it is possible to exceed current developers capacity or tray life by as much as 2x to 4x or more by appropriate formulation. This method of mixing developers with 2 activities was used in Kodak PR10 print material. It is possible. I'm just surprised that this has never been brought to fruition yet in the commercial arena.
So, this is just FYI. Stay tuned.
PE
This post is intended as a continuation and update for those interested.
Imagine a mix of 2 developing agents. One is very active but used in low concentration. Its oxidation products do not decompose. Imagine another which is much less active, but reacts with the oxidation products of the first developer, and which itself has oxidation products which decompose into less active material.
An example of the latter is hydroquinone, which when oxidized forms hydroquionone monosulfonate in developer solutions. The activity ratio of HQMS to HQ is about 20:1 or larger.
So, lets assume a mix of 0.1 gram of a highly active developer and 20 g/l of a poorly active developer. But, the pair interact to regenerate the active developer.
Now, what is the result? The result is an active developer that keeps regenerating itself. What is the result for the user? Well, this type of developer has high capacity or long tray life or both. It will yield the same results for a long time allowing process uniformity when you want to print a lot of exactly the same print. It also means that when the developer begins to die off, you can recreate the original result more easily just by increasing development time.
In fact, it is possible to exceed current developers capacity or tray life by as much as 2x to 4x or more by appropriate formulation. This method of mixing developers with 2 activities was used in Kodak PR10 print material. It is possible. I'm just surprised that this has never been brought to fruition yet in the commercial arena.
So, this is just FYI. Stay tuned.
PE
