Ink densities

[Lpool]

Hi,

I don't know if someone can help me with this issue. I'm looking for Sun Chemicals ink densities to calibrate my plates for sheetfed printing. Currently we are using SunLit Diamonds DIA 25 Process Cyan, DIA 46 Process Black & Yellow, DIA 27 Process Magenta Inks. It would be greatly appreciated if someone can help me out our guide me.

Many thanks
Andrew

[gordo]

Hi,

I don't know if someone can help me with this issue. I'm looking for Sun Chemicals ink densities to calibrate my plates for sheetfed printing. Currently we are using SunLit Diamonds DIA 25 Process Cyan, DIA 46 Process Black & Yellow, DIA 27 Process Magenta Inks. It would be greatly appreciated if someone can help me out our guide me.

Many thanks
Andrew

I doubt that Sun Chemical would have ink density targets for their ink.
I guess it depends on what you are trying to do, i.e. what you mean by "calibrate my plates."
Have you tried starting with the old standards?

C 1.40
M 1.50
Y 1.05
K 1.70

They are not specifications though.

best, gordo

[chevalier]

I doubt that Sun Chemical would have ink density targets for their ink.

If not the company making the ink determining the ideal density then who?

[gordo]

If not the company making the ink determining the ideal density then who?

The individual printshop determines the ideal density.

The industry standards organizations like ISO provide examples of typical densities, however, the density values they publish are for information purposes - they are not specifications. There are way too many variables if density is the only target.
Print standards provide specifications for the ink hue measured with your spectrophotometer at the ink densities that allows your press to print in a reliable, relatively consistent, and artifact-free manner.
So, the ink manufacturer might tell you that the ink hue complies with industrial standards like ISO 2846:1 (ink color) and therefore would help you conform to ISO 12647:2 in an offset pressroom - but that's as far as they are likely to go.

best, gordo

[chevalier]

When the ink vendor achieves conformance to ISO 2846:1 shouldn't they designate the density they used to achieve conformance? To my brain it seems like "standard" ink density should be determined based upon the chemical profile of the ink most optimally achieving its target color. ("Most optimally" being a nice and easy way of wrangling many variables into a simple phrase.) With every vendor's inks having different chemical makeups and various amounts of pigment/carrier/catalyst/initiator it just seems fundamental that the ink vendor should be designate the ideal standard density of their inks.

Where am I getting off track here?

[gordo]

When the ink vendor achieves conformance to ISO 2846:1 shouldn't they designate the density they used to achieve conformance? To my brain it seems like "standard" ink density should be determined based upon the chemical profile of the ink most optimally achieving its target color. ("Most optimally" being a nice and easy way of wrangling many variables into a simple phrase.) With every vendor's inks having different chemical makeups and various amounts of pigment/carrier/catalyst/initiator it just seems fundamental that the ink vendor should be designate the ideal standard density of their inks.

Where am I getting off track here?

Because their press condition and instruments would be different than yours any numbers they could provide would be meaningless and possibly lead to liability issues for them. Also, they would probably say that it is the job of the print standards organizations to provide such guidelines just as they do for dot gains.
In the steam-powered days of the past, organizations like SWOP provided Hi/Lo process ink density samples that the printer could measure with their instrument. Whatever density values the printer's instrument read then became the High and Low density numbers that the printer should be within. Keep in mind that SWOP does not provide specifications for the press room. But for the proofing system. There are no SID targets.

hope that helps, gordo

[saso777]

I totally agree with gordo and you should try like:
C:1.30-1.140
M:1.40-1.50
Y:1.05-1.10
K:1.70-1.80

[rich apollo]

When the ink vendor achieves conformance to ISO 2846:1 shouldn't they designate the density they used to achieve conformance?

You're also assuming that the inkset in question conforms to 2846. Many inks do not. The conditions for ISO 2846 testing are nothing like offset printing.

The original poster needs to decide what colors he'd like the solids to hit, then determine what densities achieve those targets, then decide if those are densities that can be consistently run.

[gordo]

The original poster needs to decide what colors he'd like the solids to hit, then determine what densities achieve those targets, then decide if those are densities that can be consistently run.

You blinked ;-)

best, gordo

[chevalier]

Because their press condition and instruments would be different than yours any numbers they could provide would be meaningless and possibly lead to liability issues for them. Also, they would probably say that it is the job of the print standards organizations to provide such guidelines just as they do for dot gains.

I'm still not getting it. Perhaps I am misunderstanding something fundamental here. Please educate me here. Here is the longer version of my thinking:

A solid is measured to conform to a certain LAB value and tolerance (such as ISO 2846). If to achieve ISO 2846 conformance with a specific ink a certain density range is going to exist to achieve that LAB value on whatever substrate. Isn't the density to achieve LAB conformance completely independent of the printing process/equipment and unique to that specific ink and substrate? Without this interdependence existing between LAB value and density how can measurement systems calculate density from the LAB value? I understand that density and LAB are not perfectly congruent to each other but they are interdependent at some level right?