a* b* of black ink

[dimitri]

Is anyone using/selling any blacks that have an a* and b* value of 0.00 at a 100% dot area, as specified by 12647-2 (sheetfed)?

 

[meddington]

Is anyone using/selling any blacks that have an a* and b* value of 0.00 at a 100% dot area, as specified by 12647-2 (sheetfed)?

Yep. Wikoff Hyperset (-0.1, 0.0) and Superior Elite (0.3, 0.1) are essentially there. I'm sure many others as well.

 

[dimitri]

Thanks!!!!

 

[mglouis]

Toka Bestak (-0.3, 0.1).

 

[tmiller_iluvprinting]

Sun Chemical Triumph series(0.1, 0.1)
Best regards,
Todd

 

[martin.weberg]

Ask the ink manufacturer if their ink's conform to ISO 2846-1:2006

ISO 2846-1:2006 - Graphic technology -- Colour and transparency of printing ink sets for four-colour printing -- Part 1: Sheet-fed and heat-set web offset lithographic printing

Martin Weberg

 

[dimitri]

Thanks all,

I got the 1997 edition of the standard, and unless the 2006 edition is different, the chromatic tolerances for black are a*: -0.7 to 2.2 and b*: -3.56 to 2.44.

It is well known that these are wide tolerances, and according to them the ink that we are currently using is in conformance. I am looking into wedge drawdowns between a perfectly neutral black ink and a bluish black ink to decide what would benefit us more.

Here is my dilemna: a perfectly neutral black (0,0) appears too yellowish throughout the tints and it might not be pleasing to certain customers of ours. On the other hand, using a bluish black that would not be 0,0 but looks 'better', would not match a grey balanced CMY tint reproduction scale, which operates under the 'unfeasible' assumption that a 100-100-100 CMY build is 0,0. Addition of a non-neutral black through GCR, I speculate, could also result in a cast of grey balance... at which point I question myself for over-analyzing the color of the black.

Thanks all for your replies!

 

[martin.weberg]

It is well known that these are wide tolerances, and according to them the ink that we are currently using is in conformance.

Ok

... using a bluish black that would not be 0,0 but looks 'better', would not match a grey balanced CMY tint reproduction scale

CMY correction curves could be adjusted, giving corresponding "bluish" greys.

Martin Weberg