Different shades of process colours!

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Different shades of process colours!

Postby Ramee » Tue Jun 20, 2017 6:21 pm

Is it possible receive process colours with different shades from an ink supplier. For example we are having a issue where a recent batch of Cyan is having different shade from our older Cyan inks. To this happen what could be the reason different pigment grades etc? Also is there a standard where process colours /pigments/ bases are measured. Thanks for any info on this.
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Re: Different shades of process colours!

Postby TexMaintMan » Tue Jun 20, 2017 6:36 pm

How old is the old batch? Is it printed on the same material? You can always ask for a new PMS book and a sample cyan from another supplier to cross reference.
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Re: Different shades of process colours!

Postby Frank Burgos » Wed Jun 21, 2017 11:50 am

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Re: Different shades of process colours!

Postby dants » Thu Jun 29, 2017 2:21 pm

an ink supplier should provide process colors that are mono-pigment - in the case of cyan a 15:3 blue pigment - but even this specific color index pigment can vary in shade (in case of cyan from green to red) between pigment / dispersion suppliers - demand your ink primary ingredient(s) i.e. pigment remain the same unless you test and pre-approve any changes
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Re: Different shades of process colours!

Postby inkman » Sun Jul 02, 2017 11:24 pm

It is possible to receive process colors that vary in strength and shade, even from the same ink supplier. If you order the same product code numbers from one supplier, the colors should not vary... but that is no guarantee. If you are getting inconsistent colors from a supplier using the same product code, this is on the supplier. That supplier should be confronted ASAP, and they should initiate corrective action immediately. But before you blame your supplier, make sure your ducks are in a row- no changes in anilox, stock, viscosity, etc.

If you are ordering one set of process colors from two or more suppliers, it would be unusual if off-the-shelf process colors were consistent from one supplier to the next.

Ideally, each process color should be a single pigmented ink. Often they are not. If calibration is done with G7 or GRACoL methods, it is not unusual to use two pigments to match one process color, esp. if lightfastness is necessary.
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Re: Different shades of process colours!

Postby Ramee » Mon Jul 10, 2017 6:21 am

Thanks guys! Yes its is more of an educational question as I don't have much knowledge in pigments and their qualities. Specially I didn't know primary process colours can be made from two or more colour pigments. I believe even for mono grade pigments, there can be variations and how much variation is acceptable in industry standards I am not sure! Most special colours we make are kept under delta 2 in Xrite.

We use primary colours from three different suppliers and they are indeed in different strengths, and some times different shades too. We had a job where we used pure Cyan as the main background colour as a customer requirement, and later when we reran the job and scan the colour with Xtite it was weaker and a different shade from original colour.( it was from a different supplier) How much Cyan base I added to Cyan didn't make it bring under delta 2 in Xrite scan because it was a different shade. Had to add little bit of violet base to bring it to pass in Xrite.
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Re: Different shades of process colours!

Postby T Murugadas » Thu Aug 10, 2017 7:01 am

If the Cyan is stronger, then the shade will be towards redder and if it is weaker, the shade will be towards greener. If you add violet to make a weak cyan to redder (a false strength), then there is a chance to lose fine dots in vignettes. If it is a solid, then it wont affect much.
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Re: Different shades of process colours!

Postby longtimefan » Sun Aug 13, 2017 10:47 pm

Just a FYI.. Supplies are different. We have violet from two different suppliers.. One is bluer and other is redder
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