High speed web offset problems: trapping in black, ink quality and sequense issues

[Achtung | Spitfire]

Hello,

Does anyone have any observations of trapping in K vs. C etc?
I have observed serious problems with KCMY sequense where the black ink is not the best (but still within standard when it comes to how tacky it is, the pigmentation and the Lab as compared to ISO (ISO newspaper being a bit brown though, which enhance my problem)).
We have been conducting the tests in a Colorman, newstock with variating quality.
I have to admit that I usually just measure trapping in the secondaries. Now added one parameter in the data collection: trapping between K and the colours.
Very poor trapping in K/C.
I have solved the problem now, mainly by changing one factor.
But by changing one more factor we got even better results.
Anyhow, writing from a car in Africa, does anyone else seen the same problem, have you measured trapping in K vs C, M, Y and do you have any study on it?
Cheers
Andreas

 

[Greg Imhoff]

Hi Andreas As you mentioned K is not part of normal Trap formulas.

Since you are measuring would recommend you use the Visual (K or V) filter sets with K and secondary colors, using the formulas in the attached Applied Densitometry Manual.

Let me know how this works for you.
See us at Graph Expo Booth: 3561
Greg Imhoff
President GRIPdigital, inc. & Director EPG Color Solutions
(800) 394 - 7130 begin_of_the_skype_highlighting**************(800) 394 - 7130******end_of_the_skype_highlighting - office
(708) 557 - 2021 - cell
Skype: gregimhoff
Print Properties Committee Member and GRACoL G7 Expert
Essex Products Group | Integrated Color Control Systems

Hello,

Does anyone have any observations of trapping in K vs. C etc?
I have observed serious problems with KCMY sequense where the black ink is not the best (but still within standard when it comes to how tacky it is, the pigmentation and the Lab as compared to ISO (ISO newspaper being a bit brown though, which enhance my problem)).
We have been conducting the tests in a Colorman, newstock with variating quality.
I have to admit that I usually just measure trapping in the secondaries. Now added one parameter in the data collection: trapping between K and the colours.
Very poor trapping in K/C.
I have solved the problem now, mainly by changing one factor.
But by changing one more factor we got even better results.
Anyhow, writing from a car in Africa, does anyone else seen the same problem, have you measured trapping in K vs C, M, Y and do you have any study on it?
Cheers
Andreas