CHROMiX

Grey balance in press profiling

I’ve been getting a number of press samples for profiling where the operator has managed to get the right density for all the CMYK colurs…but the grey balance is way off.
How important is it for the pressman to make sure that the grey balance is achieved as close as possible for proper profiling? Should the grey balance be be maintained before the density…or both at the same time?
How inaccurate will a press profile be if the grey balance is ignored when running the profiling target on the press?
Any inputs will be greatly appreciated…

Solids first, then gray balance. This is not an either/or scenario.

If your solids and overprints are correct, however you established this to be the case, and your gray is way off, however you’ve established what gray is, you may need to apply CtP curves to force the desired gray. You should also be concerned with the visual density of the grays.

After you have established proper solids, overprints and gray (e.g. calibration) you may tweak solids to maintain gray within reason and by reason I mean you need to be careful to avoid getting your solids and overprint out of tolerance while chasing gray. Good gray is no fun if you can’t also hit the red, greens and blues in your proof.

Learn to manipulate overprint hues regardless of saturation. Very important to tweaking densities to chase gray!!

Press profiles will be less accurate than they otherwise would be if based upon proper gray balance. Profiling software expects measured samples to be uniform. Proof to press match will suffer under poor press conditions .

Many people refuse to profile presses rather they print as similarly to open standards as much as possible. If you must profile the press, be careful not to use the press as a proofing standard or else you risk your proofs not matching client expectations. If you proof based on a specific press, getting in the ballpark of swop gray is VERY important for compatibility with client files. A better strategy with press profiles is to use them to match a standard condition such as swop2006, fogra29, whatever…

Don’t be discourage if 3/4 gray is off. This is not a realworld recipe and black ink will typically handle the neutrality in this tone region.

If you have the luxury of applying aggressive GCR to your pages, gray imbalance will be more consequential to the control strip and less so to the page you are selling to the client.

I urge you to download and read idealliance.org/filefolder/G … inal_2.pdf

For a very short and perhaps safely skewed version of this highly technical document, read the G7 on a post-it note at g7expert.blogspot.com/2008/10/ea … g-few.html

Sorry if I went on too many tangents. I made this a brief as I could at the time of writing. You gave me a loaded question :slight_smile:

Regards,
Matt Louis

Hi Matt,
That was a rather prompt and detailed reply…more that what I had expected. Thank you very much for the knowledge and I will spend some time mulling over it and going through the links.

Much appreciated.