CHROMiX

Results using Photoshop curve option

G7 was tested using photoshop curve option.
Saturation is lower than monaco profiler.

Do I need some printer driver settings?
Or g7 is not related to the printer settings?

Please let us know if you have a good way.

G7 is a process for linearization, and is not intended to take the place of ICC profiling. In fact, most users of G7 will make a profile of their system when they are finished with the G7 end of things. If you are printing through a driver, you will probably not have a need for G7, since the media settings in the driver take care of ink limiting and linearizing the way your printer behaves automatically. The Photoshop curve option is not meant to be used in actual production - it’s offered so that people can experiment and test things out in Photoshop and other analytical software, instead of using a press.

Hi Pat,

As gently as I can I must respectfully disagree with a couple of your comments:

G7 is a process for linearization

most users of G7 will make a profile of their system when the are finished with the G7 end of things

In fact G7 is (I believe) IDEAlliances Trade Mark for their implementation of the Near Neutral Print Density calibration method as listed in ISO Technical Specification 10128 Methods for Calibrating a press to ISO 12647-2.

So rather than simply a linearization tool, the G7 process - with correct variables such as ink and paper that comply with the ISO references - will in fact deliver a cmyk output that complies 100% with the ISO 12647 Standard.

The G7 methodology (or in ISO speak, the Near Neutral Print Density methodology) will deliver a predictable press result that will match relevant profiles, i.e. Gracol 2006, SWOP 3 v2 and SWOP 5 v2. In a press targeted environment as I described above, if you do it right, there is no need to make an ICC profile just use the relevant standard profiles for proofing and you will preview what the press will deliver.

On inkjet printers (or other cmyk devices) where the target is not necessarily a litho printing press I have implemented a G7 calibration in the RIP. Usually the result has been a very good grey balance to the full gamut of the printer/plotter.

Only on one occasion did I build a profile on this G7 calibrated base and that was on two older toner copier/printers that my customer wanted to use to match a corporate cmyk colour. I made a paper profile but I still needed a couple of tweaks in the RIP dot gain curves on top of the profile to get a Delta E of less than 5 for the target colour on both devices. These tweaks and the need to profile was more because of the non-linear behaviour of the devices (which were identical models) rather than anything else.

Hope I have contributed to the thinking and discussion.

Best regards,

Dan Wilson

On 13/04/2010 17:03, “Patrick Herold” wrote:

Excellent points to consider!

Thanks for bringing these up Dan.

Thank you for your opinions.

During inkjet printing testing by G7,
I thought that G7 could be apply only ISO standard inks.
And can be apply specific RIP.
Of course, I can think of because it is being tested.

Using RIP, it’s difficult to find good way.
When I input linearization value, it doesn’t have gray balance.
Also chart has color bleeding cause total ink over.
Measuring error often occurred.

When I input device link ICC profile in the RIP,
it makes some error. Sure it can be specific RIP.
Finally I couldn’t apply device link.

In the photoshop, gray balance and saturation isn’t satisfied.
So redish or so greenish and etc.
Tolerance would be exceeded.

Actually I worried about testing in other RIPs.

In printing industry, we used variable RIPs, Inks, Papers.

But I think that G7 should be good about gray balance(GB) and saturation minimum. I understand about hue difference. It can be possible.
If GB and Saturation are not good, I have no reason to use it.

I just want to know.
Offset and other printings could be apply G7.
But inkjet is much better ICC profile.
Is it right?

Sometimes I envy about offset printing standard.
But injet printing is also lovely. Cause wide gamut and simple process etc.

And really grateful for forum.

Best Regards
Nicky

G7 is more that just the implementation of NNPD in ISO. We are using it in dye sub and we have nothing to do with ISO specs at all.

Since this topic is so related to what I did, what do you think could be the problem here: [one.imports.literateforums.com/t/vpr-curves-spectral-data-but-cant-curve-rgb-spectral-data/1096/1)