Ink Consumption

[hardtemper]

Hello all !

Im student and i need little information about ink consumption in flexo printing and gravure printing. What is the consumption of 1 lb/kg per sqm/sq inch. I found table for offset ink consumption per 1lb but cant find such information about flexo ...

 

[gordo]

Hello all !

Im student and i need little information about ink consumption in flexo printing and gravure printing. What is the consumption of 1 lb/kg per sqm/sq inch. I found table for offset ink consumption per 1lb but cant find such information about flexo ...

AFAIK you can't make a generalization about ink consumption like that with flexo - there are too many variables like anilox volume, transfer factor, viscosity, ink type, ink density, etc.

 

[D Ink Man]

I would say that ink consumption is directly related to ink density and the pigment load of a given ink. If you are delivering the same real, actual density to alike substrates, the ink consumption can be directly correlated.

So here in layman terms is the understanding. Let us take an offset litho ink as an example. Let us say, for example the offset ink has 20% total pigment. A mileage guide I have always used is this for offset:

Sheet Size: 8.5 x 11=93.5 square inches.
Impression Count: 100,000
Coverage: 100%
Coated Paper: 30 pounds estimated usage
Uncoated Paper: 45 pounds estimate usage

This simple formula has worked for me for many years. So you need to know the jobs total coverage which can be figured with easy mathematics based on a solid sheet (93,5 sq., in.)

Than the impression count, which again is simple math.

Do the calculation based on the substrate.

These 3 values can get you anywhere for a good estimate.

Now these factors can certainly be effected by other things such as drastic differences in the absorptive qualities of a given stock, but that is OK.

The ink's specific gravity also has something to do with mileage, again OK. To understand best, a pigment less ink like an overprint varnish has much less volume, lbs. per gallon, versus a metallic or opaque white which has high specific gravity, or same thing, pounds per gallon.

Now that is offset. Let's look at Flexo. A Flexographic ink has say 10% total pigment load. Now we can get somewhere.

Example Now: Offset job is printing a flyer (8.5 x 11) on coated stock with total ink coverage at 50%, of the sheet printing 25M imps.. So you do the math> 93.5 sq. inches consumes 30 lbs.. 1/2 that is 46.75 sq. in. - You would need 15 lbs. for 100M, but the job is 25M, which will make your ink estimated consumption at 7.5 lbs. for the impression count.

For Flexographic, given the same substrate an ink with 10% pigment load you would use 2X that or 15 lbs. That is true only if you are running the same density.

I may have or may have not overcomplicated this for a comparison, but it is accurate. You as a printer can generalize pigment amounts for offset at 20% and Flexo inks at 10%. That should work for what you are trying to do, Remember, it has worked for me for some years, and rarely does a job run short. This can be used for costing jobs also, by print sales estimators.

I am sure many involved in different aspects of the trade have their own pet formulas and calculations that are used. All I am giving here is what has worked for me mainly in offset, and how to compare it to flexo.

I hope this sheds some light and guidance.

D Ink Man

 

[aqazi81]

Go to Youtube and a search a channel UGLY FLEXO by Frank Burgos. There you'll find your answer.

 

[hardtemper]

Thank you all for your fast responses !

Ok, yes i know there are many factors of which it depends ink consumption. I need approximate usage of ink.
Please see the attachment files. One(Fetch) of them contain info about ink mileage in offset printing and another is about ink volume in flexo and gravure printing (but im not quite sure how appropiate is this information) in this file they they claim 0,4-0,7g/m2 for proccess color and 0,5-1g/m2 for white(and im still not sure about my understandings for this file.. please correct me if im wrong). yesterday i asked same questions to one of european ink distributors and they anwsered me : "Layer thicknesses in flexo printing are between 2 and 5 micron.
So for covering 1 m² you need 2-5 gram of ink."
So i need similar like 1st file (offset ink usage table) but for flexo. I asked such of questions (Maybe they're stupid to some extent) because im not quite sure about whole this information in internet today and need to check and share this with pro's.

P.S. Mr D Ink Man i think you have a mistaken calculation

You would need 15 lbs. for 100M, but the job is 25M, which will make your ink estimated consumption at 7.5 lbs. for the impression count.

100 divided by 25 its 4, no 2, so when i need 15 lbs for 100 M and divided it by 4 = 3,75 lb or im wrong ? Another thing , used media in offset and flexo is different and have different properties i.e. absorbtion of ink, transperacy and etc. Is it correct to measure ink consumption in flexo on base of offset information about used ink per sq inch ?

 

[D Ink Man]

hardtempwer, you are correct. 30 lbs. for 100M, 1/2 coverage 15 lbs., 1/4 impression count = 3.75 lbs.

Thank you for correcting that. Proof that someone is paying attention. Thank you.

D Ink Man

 

[hardtemper]

You are welcome !

What do you think about the other things ?

In attachment file you can see one of the methods for calculationg amount of needed ink. Notice what is written with blue font in point 4 (You can not calculate the coverage area for 1lb. of think. This value will ALWAYS be given to you.) So i needed exactly this information with 1 lb how much area can be covered. I turned to couple of ink distributors and ask them for this info but nobody gives me the anwser :/

 

[D Ink Man]

hardtemper, I looked at that and that is OK, however back to my EZ formula using offset as Standard. I am better awake now.

Offset Ink
1 lb. of ink for a solid sheet 8.5 x 11 will give you 3,333 impressions on coated stock.
1 lb. of ink for a solid sheet 8.5 x 11 will give you 2,222 impressions on uncoated stock.

After knowing this you can base any calculation necessary for ALL the print processes, except perhaps Digital.

Generally offset and flexo use the same type pigments for general work. Offset pig load 20% and flexo pig load 10% can take you the rest of the way.

Letterpress will use 2.5x more ink vs. Offset.

Gravure will use 3x more ink vs. Offset.

Intaglio will use 5x more ink vs. Offset

Digital, since these colorants are more times often than not, DYES, will use more ink versus normal conventional PIGMETS used in the traditional print processes. Pigments are normally STRONGER than DYES.

Another one, generally the more lightfastness pigment will be WEAKER vs. a pigment that is more fugitive, or less sun lightfastness.

Pigments have more LIGHTFASTNESS versus DYES.

Remember this> Ink Colorant Percentage + Print Density = Ink Consumption
This is a generalized formula statement you can count on.

More information, more help, I hope.

D Ink Man

 

[hardtemper]

1.So if i multiply 8,5x11 = 93,5 x 3 333 imp = 311 635 sq inch with 1 lb ink, right ?

2.Those values are referred for 100% coverage?

3. I cant understand this - "Another one, generally the more lightfastness pigment will be WEAKER vs. a pigment that is more fugitive, or less sun lightfastness." isn't it the opposite ? Im not quite sure that im understand what you said . Can you explain me please ?

And thank you about everything !

 

[D Ink Man]

A standard 'letter size' 8.5 x 11 is used just because it is a 'standard' size. 93.5 square inches just happens to be the consequencing result. Back to one pound usage> Coated paper, 'standard size' SOLID coverage. 100,000 impressions will use 30 pounds of ink, coated paper. By calculation 100,000 divided by 30 equals 3333; the number of impressions you can get from one pound of ink.

Lightfasteness stability generalization: A stronger tinctorial strength yellow like Benzideine yellow Pigment 12 (C.I.) has more tinctorial strenghth versus a Hansa or Hostaperm pigment type which has less lightfastness. What was said is true, for most colors, not only yellow; however a basic generalized statement.

D Ink Man

 

[hardtemper]

Another one, generally the more lightfastness pigment will be WEAKER vs. a pigment that is more fugitive, or less sun lightfastness.

Ok but i still didnt get it ...

Lightfastness - The lightfastness or permanence of a pigment is its resistance to change on exposure to light.
fugitive- pigments are impermanent pigments that lighten, darken, or otherwise change in appearance or physicality over time when exposed to certain environmental conditions, such as light, temperature, humidity, or pollution

this what i am understanding from those facts about light fastness and fugitve isn't it the opposite(more light fastness ink will be STRONGER than fugitive)?
In general What do you mean with that in which light fastness pigments is weaker than fugitives ?

Thank you for patience !

​​​​​​​have a nice day !

 

[D Ink Man]

Ok but i still didnt get it ...

Lightfastness - The lightfastness or permanence of a pigment is its resistance to change on exposure to light.
fugitive- pigments are impermanent pigments that lighten, darken, or otherwise change in appearance or physicality over time when exposed to certain environmental conditions, such as light, temperature, humidity, or pollution

this what i am understanding from those facts about light fastness and fugitve isn't it the opposite(more light fastness ink will be STRONGER than fugitive)?
In general What do you mean with that in which light fastness pigments is weaker than fugitives ?

Thank you for patience !

​​​​​​​have a nice day !

This may make it more understandable. Ink, 20% pigment containing. One has pig 12 (Strong), one has pig 174 (Weak). Pig 12 ink prints 4x higher density value versus Pig 174 ink. Let's say Pig 12 prints ay yellow density number of 1.30, (I know that's high for reflective density). Let's say Pig 174 prints at density number of .75 (I understand that is low). If you subject both to sunlight, the Pig 12 ink will fade to blank paper in 72 hours. The pig 174 print will last 1 month with little degradation or loss of density.

Maybe that helps unless alibryan can explain it better. He seems to know much about all with few words.

D Ink Man

 

[hardtemper]

Guys, thank you very much for the patience and the answers !

Have a nice weekend !