I'm curious (Erik/Gordo) if you could create a press side color management program what would it entail? I think if I have followed you both successfully Erik you think gray balance is 1 of many things that should be evaluated and Gordo you are more skeptical of gray balance as a whole. You have proven in press runs that you could maintain pleasing color in the live area of newsprint while being out of gray balance when using GCR and FM screening. To be clear I'm asking from a curious standpoint, not critical.
Wow, this is actually a big question and this place is not the place to discuss details. But I will try to break it down to the essentials of how I view the problem. Gordon views things from a much more practical and thoughtful perspective on how the process now exists, while I have tried to understand and think of possible solutions from a theoretical perspective on how the process could exist.
My thinking applies to any printing process even though my main interest has been in changing the offset lithographic process.
Let's just think philosophically about this problem.
If you have a printing device/process and the output is repeatable, consistent and predictable, then the output is determined and can be known.
If you have a printing device/process and the output is not repeatable, not consistent and not predictable, then the output can't be known and you have to adjust after starting and hope you can reach sellable output and continue adjusting the process to try to maintain sellable output.
The reality is that offset and even digital printing lands somewhere between these two extremes.
So in general, one can not apply, even a perfect prepress colour management concept, to an inconsistent printing output device and expect consistent and predictable results.
For this reason, I have tried for a long time to state that what was important was to make the offset process consistent and predictable first. And to do that requires first to correct the ink feed problem. Nothing else can be done until that is done.
So to address your question, with respect to how I see the problem, I say that the first step would be to make the offset process consistent and predictable. This means that the press goes to the desired running targets without any adjustments by operators or closed loop control. I expect the press would be in colour within 50 impressions. This is based on computer simulation runs done 25 years ago.
In such a situation there is little need for colour bars or gray patches although they would be good to have to catch breakdowns in the process but not for control during normal running conditions.
Colour management could also then be much more straight forward. Since the colour output would be consistent and repeatable, mapping the output would make it predictable. This means that if one has a simple, quick and accurate way to map the range of colour the press will print under specific conditions, then that can be used to drive the prepress process. There would be not reason to use standards or tone curves or G7 or gray patches. All the information of how the press can print would be in the mapped data.
Now ICC does this type of thing but uses a limited number of measuring points. For a CMYK print on an offset press, if we think of each plate having 101 possible percent dot exposures, from 0 to 100 percent, there are 101 to the fourth power combinations of screens possible. That is 104,060,401 possible combinations, each that could possibly result in a slightly different colour when printed at some standard SID values with a specific ink set and paper combination. If an ICC profile has only a little over 1000 measured points, then one can see that is not going to accurately describe all the combinations. More points are better for accuracy.
What is needed is to measure thousands of points very quickly. One can not do this by hand of course. I have known that a device to measure so many points would be required and have waited about 15 years for some technology to come out that can do this. So now there is a company in Germany that is selling a device that can measure 10,000 points all at once. I would not name the company because I don't know how well their product works but that kind of capability is needed to move the industry forward.
So if you had new presses or even old presses that were modified to be consistent and predictable, then you could just quickly run a test form with 10,000 small patches and have it measured and your prepress could use that to provide predictable colour matched to your consistent press. No hours of running forms, G7, guesswork, hope etc.
This does not help you with your problems today. Gordon will be more helpful for you on this. But I will say that I have been looking at this problem for the mid 1980's. I presented a paper at TAGA in 1997 about some of these issues that needed to be addressed. There has been absolutely no interest on the part of the experts in this field to change much and that is what Gordon and I have complained about. Their disinterest over the years has hurt printers like yourself.