GRACoL2006 vs GRACoL2013

[lnivin]

One of the test images I've been using for testing shows a great deal of difference between GRACoL2006 and GRACoL2013. Attached are the Cyan channel screen captures of each profile (left is GRACoL2006, right is GRACoL2013). Quote from IDEAlliance - "GRACoL 2013 is almost identical to GRACoL 2006".

 

[Colorblind]

From what I could see on my screen and by comparing resulting CMYK values, the 2013 version uses a stronger GCR black and CMY gray balance is less yellow from the midtones to shadows than it used to be.

 

[meddington]

Quote from IDEAlliance - "GRACoL 2013 is almost identical to GRACoL 2006".

That is true, but separation characteristics may depend on the software that created the profile, its GCR/black generation characteristics, the CMM handling the conversion, the rendering intent, etc. The second thumbnail seems to show much more aggressive GCR than the first. This may have nothing to do with the difference between Gracol 2006 and Gracol 2013, and everything to do with the characteristics of the ICC profile. Do you know the source of these profiles?

 

[lnivin]

Both came from IDEAlliance. But I'm still testing. Other images seem to be closer to the same, have the look of GRACol2013 in the above images.

 

[meddington]

Only thing I would recommend is that if the separation consistency is important, you may want to obtain the characterization data and generate your own profiles.

 

[Stephen Marsh]

Inivin, please see my replies to your other two topic threads:

http://printplanet.com/forums/color-management/33667-between-sheetfed-coated-swop-gracol2006
http://printplanet.com/forums/color-management/33665-between-uswebcoated-swop-gracol2006

CMYK is a device dependent space. There are different “flavours” for a reason.

I can have an image that is CMY with no K, which is targeted to say Fogra 39 print condition. I can also have the same image in CMY with a lot of K, which is targeted to say Fogra 39 print condition. Both are separated using different profiles. Each profile has different GCR ratios set in them. However both profiles were created from exactly the same measurement/characterisation data!

They are both F39 - even though one has a lot of black and the other no black.

I can convert an image to say ISO Coated v2 300% ICC profile (print condition). I can then assign the Fogra 39 ICC profile to this image (or ISO Coated v2). The colour and tone will not change (perhaps only 1 point in L*, a* or b*). Why? Because they are both the same print condition, despite having different GCR levels, different total ink limits and being made using different ICC profile creation software. Both profiles were created from exactly the same measurement/characterisation data!

Now try to assign the SWOP profile to the GRACoL image. The colour/tone will indeed change. Why? They are different print conditions.


Stephen Marsh

 

[lnivin]

Stephen,

Does your explanation above have anything to do with one of my other questions -

http://printplanet.com/forums/kodak...gy-destination-different-indesign-destination

 

[Stephen Marsh]

Stephen,

Does your explanation above have anything to do with one of my other questions -

http://printplanet.com/forums/kodak...gy-destination-different-indesign-destination

It is hard to say!

I think that we need to be clear on what exactly a device (print/press) condition is first… We need to go back to basics, everything you are trying to do revolves around your press print condition.


Stephen Marsh

 

[lnivin]

Press was fingerprinted using an IT8.7 chart and a plate curve to be G7 certified.

Is that what you are asking?

 

[Stephen Marsh]

Press was fingerprinted using an IT8.7 chart and a plate curve to be G7 certified.

Is that what you are asking?

Do you have the measurement data of the press?

Do you have an ICC profile created from the fingerprint of the press?

How do you verify that what you print today is within tolerance of when the press condition was certified?

G7 does not mean that the press condition is GRACoL - it could still be a custom house condition, however G7 can also be used to get to GRACoL.


Stephen Marsh