Offset Ink Mileage Test Procedures

[D Ink Man]

If anyone knows the best method to very accurately measure ink mileage, Ink A versus Ink B, please offer it here to this post.

I have had a bit of experience with this subject and will share my methodologies to the forum henceforth.

Thank you everyone in advance for your experiences and contribution.

D

 

[gordo]

If anyone knows the best method to very accurately measure ink mileage, Ink A versus Ink B, please offer it here to this post.

I have had a bit of experience with this subject and will share my methodologies to the forum henceforth.

Thank you everyone in advance for your experiences and contribution.

D

Here's one way.

For a single color, create a test form with randomized solid and screen tint patches.
Bring the press up to a desired solid ink density and mark the delivery stack at that point.
Run the press at that ink density.
When the density drops to - 0.05 of the target mark the delivery stack.

Repeat process for the second ink.

Then weigh the two stacks. (You can also count the number of sheets).

The one that weights the most (or has the most sheets) has the greatest ink mileage.

Divide one into the other to get the percentage for the extra mileage.

Another similar method would be to:

Hang the plate with the test form of randomized solid and screen tint patches. Then bring the press up to density and balance the ink keys across the sheet.
Then empty and clean the ink fountain.
Then put a 454 gram (1 lb) charge of ink into the ink fountain. This would give a run of about 3,000 to 4,000 sheets.
Start the press and carefully observe the amount of ink in the fountain.
When it's near depletion and starts to fall very rapidly, stop the press.

Do the same with the second ink.

Then count or weigh the number of sheets in the run that maintained in the same SID.

best, gordo

 

[Deleted member 16349]

If anyone knows the best method to very accurately measure ink mileage, Ink A versus Ink B, please offer it here to this post.

I have had a bit of experience with this subject and will share my methodologies to the forum henceforth.

Thank you everyone in advance for your experiences and contribution.

D

With a positive ink feed, the test is straight forward. Print to density with one ink and then print to the same density with the other ink. Best if what is printed is all a solid. Then just compare the two ink fountain roller speeds. That should give a reasonable numbers. Not perfect but reasonable and maybe more related to what happens on press.


In a slightly different situation, using my positive ink feed technology on a Drent Goebel test press (2004), we obtained data for the ink mileage curve in about 15 minutes on press. Obtained density values at different ink fountain speeds. I have a method that only requires two data points to be able to plot a reasonable curve but one could also just take multiple density readings at different ink fountain roller speeds.

 

[D Ink Man]

So Gordo and Erik, before I go into thesis.

Is color strength and pigment load of two different inks directly proportionate to Offset Lithographic Ink Mileage?

I anxiously await your replies.

I value both of them in very high regard, as both your intellects are truly beyond that of most mortal men.

Sincerely,

D Ink Man

 

[Al Ferrari]

Here's one way.

For a single color, create a test form with randomized solid and screen tint patches.
Bring the press up to a desired solid ink density and mark the delivery stack at that point.
Run the press at that ink density.
When the density drops to - 0.05 of the target mark the delivery stack.

Repeat process for the second ink.

Hi Gordo,

The basis of the test seems to be to obtain some measure of how many sheets can be printed with the ink charge on the rollers without the further addition of any ink.

I think you forgot to mention that once the start ink density has been reached, the ink fountain should be turned off. Or did I miss something?

Al

 

[gordo]

Hi Gordo,

The basis of the test seems to be to obtain some measure of how many sheets can be printed with the ink charge on the rollers without the further addition of any ink.

I think you forgot to mention that once the start ink density has been reached, the ink fountain should be turned off. Or did I miss something?

Al

You run until the ink in the fountain is nearly depleted. At that point the density will drop very rapidly.

thx, gordo

 

[gordo]

Is color strength and pigment load of two different inks directly proportionate to Offset Lithographic Ink Mileage?

If I understand you correctly - the assumption is that with a higher pigment load you would run a thinner ink film thickness to achieve the same measured density. In tests that I've been involved in, running a thinner ink film thickness accounted for about a 3% reduction in ink usage for a given number of sheets printed. But running thinner ink films can be problematic.

I value both of them in very high regard, as both your intellects are truly beyond that of most mortal men.

I wish you wouldn't write things like that as it reads like damming with faint praise.

best, gordo

 

[Al Ferrari]

Well thanks for your indirect acknowledgment that I am indeed not understanding the basis of method. But I am baffled by your continuing to be obscure about it. This isn't like you.

Then if the fountain feeds are not turned off, then the initial amounts of ink in the fountains needs to be the same for each ink test by some measurement, no? Please help me understand this.

Al

 

[D Ink Man]

If I understand you correctly - the assumption is that with a higher pigment load you would run a thinner ink film thickness to achieve the same measured density. In tests that I've been involved in, running a thinner ink film thickness accounted for about a 3% reduction in ink usage for a given number of sheets printed. But running thinner ink films can be problematic.



I wish you wouldn't write things like that as it reads like damming with faint praise.

best, gordo

Gordo sir,

I was very sincere when I wrote that statement about you and Erik. Both of you gentlemen contribute to the forums and provide experiences and intellect that I admire and highly value.

I apologize if that came across in any other way than that. I know that sometimes I blend in some humor and sarcasim in my replies, but God strike me down, that was not my intention with that statement. Maybe I shouldn't have put that wording in about mortal men. Again I am sorry. I hope youu understand and forgive me.

Respectfully and Sincerely,
D

 

[fiatlux]

I have had a bit of experience with this subject and will share my methodologies to the forum henceforth.

Is it henceforth time yet?

FL

 

[D Ink Man]

Never on Sunday fiatlux. It is the day of rest.

 

[Dan Roll]

I rarely consider improvements in mileage to be a benefit to anyone but the book keeper, as better mileage means printing thinner ink films of higher pigment content and lower vehicle content.
1 Any variation in film thickness will be more serious the thinner the film is
2 A thick film of ink looks a lot better (especially on poor stocks) than a thin film
3 Even four layers of a thin film still looks thin
4 The ink vehicle performs the functions of ink I associate with runability (transfer, ink/water balance potential, setting and drying, etc) and the reduction of vehicle content reduces all of these
5 The savings involved in running less of a stronger ink are difficult to measure and one reason for this is these savings may not always exist
6 The stronger the ink, the more difficulty running light coverage
7 The stronger the ink, the harder it is to achieve high densities
A big ink company that was able to manufacture stronger ink than their competitors popularized strong ink (they were selling on the corporate level where those who had to run the ink had no input whatsoever) despite the fact it rarely ran as well as the ink it replaced. The purchasing agents received bonuses for trying to save money and pressroom managers were fired for failing to deliver the savings. Is it a coincidence that many of these plants are now closed?
Other than that, I love strong ink.....

 

[D Ink Man]

Mr. Roll very well written.

Only one question, #7?

Do you feel that a stronger ink is more difficult to deliver higher densities because there is less vehicle which imparts less ability to transfer?

Sorry for maybe answering my own question, but could you confirm or comment on that please?

 

[Dan Roll]

I agree with your description. The explanation I use is when you add varnish to ink you improve the transfer faster than you dilute the color. One of my diagnostic questions (usually for web printers having one difficulty or another) is 'have you recently improved ink mileage?'

I long ago worked for a company printing yearbooks, and management (they were all from the photography side of the business), while happy with the process color books, were constantly complaining that the black and white books were not 'black' enough. I tried various ink manufacturers and experimented with stronger pigment loadings for years, making no progress whatsoever (I was no smarter then than now). One day I hired an old timer (probably younger than I am now) who wanted to work part time running the 25" Harris single color with MicroFlow dampening that produced most of the short run B&W work. After an hour on the job he came to me and said he couldn't work with the ink I had and wanted permission to modify it. I told him he could do anything he wanted as long as it worked and gave it no more thought. An hour later management was carrying this guy through the halls spreading rose pedals at his feet as the work coming of the old POS (as we called the Harris) was just what management wanted; it was as black and glossy as B&W prints on Kodak photo paper!

What he had done was mix my 'super dense black' about 50/50 with clear gloss varnish. I ran the press that afternoon and noticed the ink water balance (it had been notoriously fickle on this machine) was easy to achieve and stable, the work was glossy and crisp, and when backing the work up there was no ink on the impression cylinder or register board. The next day the bindery told me the work coming of the Harris was the first time they considered any of the work coming out of the pressroom to be 'dry'. I later determined this was not a drying issue as such, but an absence of chaulking that was causing the work to mark when folded gathered and trimmed.

In the ensuing thirty years I have encountered hundreds of customers in the same boat I was in and the suggestion that they add varnish to the ink to address low density or lack of gloss, or picture framing, or piling, or narrow ink water balance is usually met with either hostility or a look of 'are you nuts?', until they try it. Never fails, but also rarely fails to arouse hostility in the ink supplier so I am usually circumspect when advising people to augment their vehicle content.

 

[D Ink Man]

Excellent story, have utilized the same type methods also. And... I must admit; I Luzzzzzzzzzzzz me some weak ink.

Real Life Story:

This goes back about 15 years. A printer, Ringier America in Corinith, Mississippi, printed the most prestigious publication, maybe on the face of the earth. It is known as National Geographic Magazine.

The vice president of my ink company at that got a call from National Geographic and also from the plant manager in Corinth. Keep in mind, our inks were used to print the cover and text of the monthly magazine. However, they were printing a special insert map of the world using a Brand X local ink suppliers inks. They liked to give a little business to everyone to keep the synergies moving.
Going on, I was based in Maryland and I received a call from my VP about the problem. This was on December 23rd and I was scheduled to be on vacation from that time until after the first of the New Year. My VP asked me if I would travel to Corinith to help them with their problem. I took a deep breath, realized the importance of being a Service Technician, and agreed.
The problem there were having was with a green on the map, very light coverage and fine lines. There were at least 8 colors on this job, printing as spot, rather than process build. So, upon arrival, I went through the press, looked at the print copies and started my diagnosis. Using an ink film thickness gauge, I measured each ink's thickness in each printing unit. I was getting normal thickness readings in all units but the green. It so happens I could not even pick up any ink off the vibrator because the ink was so starved out. The local Brand X techs did all kinds of adjustments to fix the problem. They added heatset oil, vaseline, Crisco, water fighting agents, castor oil and who knows what else. Once I had taken my thickness reading, I chuckled to myself, the problem was quite evident. The ink was much too strong, no replenishment was going on and the Brand X was being bombarded by the effects of lithographing and hanging in the ink train too long. I went to our facility in Corinth, matched the color of course with lightfast inks but cut the strength by 60%.
They put this ink on and within 5,000 impressions they realized the problem was fixed. No more green density up and down, no more washed out green, just a nice smooth laying map line that produced a perfect print. Afterwards, the on site National Geographic representative thanked me whole heartily and I headed back north to spend the rest of my vacation holiday with my family. That was the best Christmas I ever had.
Shortly after, at the beginning of the year the president and VP of the ink company received a formal thank you letter from National Geographic thanking our company for our very serviceable efforts. Needless to say, Brand X moved out of town shortly after and my company enjoyed all the ink business for that plant. That is how you obtain "Customers For Life". Do that extra SERVICE and the world shall be your oyster.

D Ink Man

 

[gordo]

D Ink Man - will you be sharing your ink mileage comparison methodology as promised?

Best gordo

 

[Lukew]

I rarely consider improvements in mileage to be a benefit to anyone but the book keeper, as better mileage means printing thinner ink films of higher pigment content and lower vehicle content.
1 Any variation in film thickness will be more serious the thinner the film is
2 A thick film of ink looks a lot better (especially on poor stocks) than a thin film
3 Even four layers of a thin film still looks thin
4 The ink vehicle performs the functions of ink I associate with runability (transfer, ink/water balance potential, setting and drying, etc) and the reduction of vehicle content reduces all of these
5 The savings involved in running less of a stronger ink are difficult to measure and one reason for this is these savings may not always exist
6 The stronger the ink, the more difficulty running light coverage
7 The stronger the ink, the harder it is to achieve high densities
A big ink company that was able to manufacture stronger ink than their competitors popularized strong ink (they were selling on the corporate level where those who had to run the ink had no input whatsoever) despite the fact it rarely ran as well as the ink it replaced. The purchasing agents received bonuses for trying to save money and pressroom managers were fired for failing to deliver the savings. Is it a coincidence that many of these plants are now closed?
Other than that, I love strong ink.....

There we go again, the false assumption that to have better ink mileage the ink needs to have higher pigment.

Solvents - solvents - solvents - solvents in the fountain solution
Please one of you ink/product techs that are blind to see that this doesn't need to be the case. Take your ink set run it up on your testing press with its current fount and run XXXXX sheets , now add 20% IPA and tell me what happened to your ink mileage. (I'm sure it went to shit and you had to use more due to the solvency towards the ink from the IPA)

The same goes for a fountain solution that is a glycol solvent base compared to one that contains no solvents. Now your going to tell me that a non solvent based fount doesn't work. Ok so I'm sure you spent many years beta testing modified ink sets to see if you could come up with an ink formulation that works with a non solvent based fount to come to that conclusion?

Or did you simply use the inks that still have the same formulations in them as they did years & years & years & years ago?

The problem is that people have spent so many years in the industry following what everyone else does that they become blind that there can be a different way.

 

[Lukew]

No more responses on ink mileage?

 

[D Ink Man]

There is a specific procedure to use when conducting offset ink mileage testing.

It needs to be conducted by an individual that is fully versed in the procedures for results that have no question into authenticity.

This procedure will result in a printer saving tens of thousands of dollars in a years time.
It will also improve the productivity and effective operation of the printer's manufacturing. This additionally leads to cost savings and the printer being absolutely more competitive in their market place.

 

[Green Printer]

D Ink Man

Do customers procedures count? With 6 months or 1 year of records showing reduced ink purchases doing exactly the same rerun and quantities of packaging jobs count as a versed and authenticated procedure?