Roger, Interesting…
Perhaps I need to add a bit of context to my original post...
You see, I may land a job with a printer who routinely prints packaging on an 8 color Roland offset press.
As you may know, packaging is typically printed on, say, 20pts recycled board or SBS, using 50" and 56" wide 6 colors presses, with mostly CMYK and two spot inks.
This particular printer claim they try to avoid printing with 6 colors to print instead with 7 colors, CMYK + RGB, for economic reasons.
My first thought would be that that’s extremely odd. From my experience — which is exclusively in large-format inkjet but still I think applicable — what I have seen is that there is absolutely zero advantage in an actual CMYKRGB inkset. The reason being that RG & B can always be made from CMYK. There’s no gamut gain to adding them. In fact, from the few times I’ve seen inksets that actually were trying to use RG or B, what I’ve seen is the profile-making engine get confused as to which is the true primary to map to, the combination primary or the solid ink primary. The results I’ve seen have been pretty much useless. That’s why every “CMYKRGB” inkset that I’ve seen in large format is in actuality CMYKOGV. I’ve always figured the “CMYKRGB" stuff was just marketing. “Hey, these guys always talk about CMYK and RGB. Let’s just call this CMYKRGB, and it’ll look like we’re using them all!” I’d be curious just what primaries these guys are actually using.
They say they developed a custom multi-color profile which they supply to clients who want to directly convert their artwork to their press in Photoshop.
Wow. All I can say is that I would not advise anyone to do that. Any time. Ever. If they want to send out a profile for soft-proofing, fine. But the only way a client can do that is the way I showed you previously. I wouldn’t take that chance. More importantly though, I’ve had some talks with some potential clients who have been attempting something similar, and every single one of them has been looking into such a system as a way to run one setup and hit the entire Pantone Library. And if that’s the goal, Photoshop doesn’t really come into the equation. Most every designer who makes artwork for such a process is going to create it in Illustrator, send the art as a .pdf, leave the spot colors defined as spots, and the goal of the profiles and the RIP is to make them match their solid PMS equivalents. Honestly, it sounds to me like these guys are barreling full-throttle ahead down a dead-end street.
What's interesting, to me, is that, from a production efficiency standpoint, by converting most jobs to this 7 color printing scheme, they effectively avoid wash-ups, reduce custom inks inventory and considerably reduce make-readies since they minimize the number of printing sequence change and can get a better utilization of press time overall.
It’s theoretically possible. Lots of people have looked into it. Whether anyone is actually there, maybe someone else on the list who plays more in that arena would know. Mike