Offset Ink Mileage Test Procedures

[Dan Roll]

Alois,

I have never met a printer (myself included, although I have not actually been paid to run a press since the 1980's) who, at one time or another, has not 'dosed' their fountain solution with one thing or another and plenty of companies make good money selling additives to be added to fountain solution (some good, some useless, some very damaging).

The only thing that really gets printers in trouble in this area is the mid-set that a good fountain solution keeps the plate background, dampening system, blankets, and circulator 'clean' leading to the very sensible (but totally wrong) idea that fountain solution is a cleaner and when not working as hoped, would benefit from the addition of some soap. I have watched printers put hand cleaner, dish soap, a product called 'Lestoil' (a floor cleaner), among other things into their fountain solution, usually to try and overcome sensitive plates, with sometimes ridiculous results.

[Lukew]

you do not see ink companies who own fountain solution companies (Sun/Rycoline, Flint/Varn, etc) promoting or even suggesting special compatibility.

So what would you call the promotion of the LIBRA series from flint? Marketed as BALANCE, HARMONY, STABILITY
To me it looks like they are marketing a system they are saying has been developed to work together! But then again I'm just a stupid printer, what would I know.
http://www.flintgrp.com/en/news-info...Technology.pdf
Europe - Flint Group Print Media announces the launch of LIBRA ink & fount technology - Flint Group

Dan, the post of mine in this thread were to outline the fact that a fountain solution "CAN" effect ink mileage. so far all the ink techs disagree with this..
Well tell me this if fountain solution has zero effect on ink mileage, does this mean I can add what ever I like and it won't alter mileage at all?
Maybe throw that fount back in that has 85% glycols and run it at full strength, hey what the heck, what about throwing a good 15% IPA in there.... Great to know that somehow inks have the ability to withstand solvents and not have their mileage altered at all...
Damn, so all that marketing regards alcohol free printing and "increased ink mileage - brighter/denser colours, from all the manufacturers and technical papers is just a crock ay....

[Dan Roll]

Did you not start the thread 'Ink & Fountain solution Designed & Developed to work together'? I suppose then you are using one of these ink/fountain solution combination and are happy with it. My experience with these combinations in the past has usually been in the form of being told by a VP of Marketing that he has signed a deal to promote a particular fountain solution in conjunction with an ink company promoting an ink. These deals more often take place in a bar than in the laboratory or in a pressroom and compatibility is assumed rather than confirmed.

As for an '85% glycol fountain solution' at full strength (lets say 4%) that produces a fountain solution that is still 96.6% water. When doing ink/water testing have always found it interesting that many researchers only evaluate fountain solutions without using plain water as a control. More often than not, ink/water numbers (regardless of the method used to produce them) are better with fountain solution than when running water alone. Does this mean water is bad?

I am not surprised that ink people do not think fountain solution has a significant effect on ink mileage, although I could introduce you to people that have made the claim that their companies fountain solution would save a major US web printer millions of dollars a year in ink. The customer bought this line and adopted this companies products (it took several different fountain solutions to meet the need) but no savings ink ink were ever documented. My friends ink the ink business that were supplying these plants reported no measurable change in ink consumption vs press time.

The companies marketing IPA replacement products probably used the same verbiage in the past to sell alcohol, why would you expect them to ever change? They are marketing people after all....

[Lukew]

Dan, No we don't use a developed system (ink/fount) as it isn't available in our Country.
The system I speak of, yes we have trialed and it exceeded any other ink/fountain solution combo we have ever run on the machine.

I put this forth to the ink techs.
We had been running for a period of time with our fountain solution having 3% IPA in it (a true digital readout). The cip 3 profiles for coated/uncoated stocks had been fine tuned, so that colours were correct from the profiles.

We then ran half a job then dumped the fountain solution flushed and cleaned the system & refilled with fresh fount but 0% IPA, we then washed decks up and then inked up again with the set pre inking and pulled some sheets. Density was through the roof and continued to climb..

I then adjusted profiles and dropped the ink keys by a large amount along with ink sweep. to bring density back into line.

I am now running uncoated stock on the old coated profile (the one that we used when 3% IPA was in the fount)

Please tell me your thoughts, Do you think ink mileage has changed at all ?

[Dan Roll]

Lukew

I have several questions before I try to answer yours;
What plates are you using?
What fountain solution are you using?
What is the specific gravity of the alcohol you buy?
When you cleaned your fountain system, what did you clean it with?

[Lukew]

Dan,
Fount = ABC
Plates = polyester
IPA Specific gravity = Unsure
Systems cleaner = Hurst

I'm positive that the IPA acts as a diluent towards the ink, effecting ink mileage.

[Alois Senefelder]

Lukew,


Yes, IPA is a known Lithographic Ink - Diluent

You should buy - 99% Anhydrous Isopropanol



Regards, Alois

[Al Ferrari]

Why is it important that the Isopropanol be Anhydrous, if it is to be added to water based fountain solution???

Al

[Dan Roll]

Lukew,

Your description of removing the IPA and then having the ink density high at the same settings is what we expect to see, but diluting or thinning the ink is not the only cause at work here. One of the problems with polyester plates is the silver halide image is not very oleophilic. Most people blame polyester plate problems on the properties of the plate background, but the image area is not going to work very hard to remove ink from the rollers and the image is easy to 'wet' with surface active agents. When you removed the IPA, the ABC fountain solution (is this Allied All Star under private label?, I think it might be) still did a good job of wetting the polyester background, but was dramatically less capable of wetting the image area, allowing better transfer of the ink in the rollers, thus the higher density. I suspect if you were able to measure precisely the amount of ink used to print the job with or without IPA there may not be much difference, you just have to have more ink in the rollers to effect the same transfer to the plate when running IPA.
IPA is technically not a surfactant, but a surface tension lowering solvent and will help water wet whatever it comes in contact with more or less equally. The surfactants in your fountain solution represent a mixture of hydrophilic and oleophilic components in a particular ratio that allows the fountain solution to wet the plate background, but not the image area.
My question about the gravity of your IPA is based on the gravity of IPA should be 0.79. It will not be lower than this, but if it is higher, it means the alcohol is diluted with water (unfortunately a common practice). If you can measure the IPAs' gravity you can determine its purity and if impure, how much water is in it. A web printer on the South Island next door to you all was buying IPA containing 20% water, a clue was they thought they were getting a good deal.

[Lukew]

Good info Dan, thanks for that.
No not using the allstar, found that particular fount less then desirable.