G7 for spot colors?

[gordo]

I've been told that "G7 calibration can be used spot colour"

But G7 is a method to bring a 4/C process into grey balance so I don't see how it would apply to a single spot color. Perhaps they are referring to the shape of the dot gain profile running from 1%-99%?

Usually the*shape of the dot gain profile mimics the shape of the Black printer as that is simple to think about.

Other people choose to mimic the closest density of a process color. E.g. dark spot colors would mimic the Black ink curve, medium density colors would mimic Cyan or Magenta, and light spot colors would mimic the Yellow.

Any clarification would be helpful.

Thanks

 

[csawatzki]

I can only guess that using the curve that is applied to a single unit on a press would assist in keeping your spot color at the proper % through a curve, taking into account the gains for that unit and environment.

Cory Sawatzki
Spotlight Print Consulting
[email protected]

 

[chevalier]

G7 is a method to bring a 4/C process into grey balance so I don't see how it would apply to a single spot color. Perhaps they are referring to the shape of the dot gain profile running from 1%-99%?

Folding carton guy here...
Yep. It's likely dot gain compensation curving getting misunderstood as G7. However, I would assume the G7 methodology is sound for use in CMYK+, expanded or alternative gamut ink sets. Of course you'd have to very carefully set your own standards to target to and include your ink vendor in the mix.

Side note: We've utilized G7 for years and I very recently had a lengthy discussion with our press room (including managers and supervisors) explaining that G7 is a method not a standard. It seems pretty clear most of the guys couldn't grasp it despite using analogies. I wanted to do a paper test to verify who actually understood it and who didn't but the higher ups poopooed it.

 

[Morgan Manning]

I've been told that "G7 calibration can be used spot colour"

Other people choose to mimic the closest density of a process color. E.g. dark spot colors would mimic the Black ink curve, medium density colors would mimic Cyan or Magenta, and light spot colors would mimic the Yellow.

Thanks

From my experience, colors below 1.6 density did well with 16% gain, and above 1.6 density fared better with 19%. I hope that makes sense (?).