Além do CMYK e RGB

[Diniz669]

Bom dia, seria muito util e agradavel se adicionassem a opção de "CMYKOGV" pois o mercado da grafica e design sempre estão evoluindo numa constancia inacreditavel pois sempre tem novas ideias de todos os lados, e adicionar o CMYKOGV seria muito util pois as novas maquinas estão usando esse sistema de "heptacromia" ou "gama expandida".

[Mike Witherell]

https://www.pantone.com/articles/color-fundamentals/understanding-different-color-spaces

[Monika Gause]

Just working in RGB and leaving the rest to RIP does not do it for you?

[Jacob Bugge · Accepted solution]

Diniz,

I presume you wish to be able to see the actual limits relative to (s)RGB on screen, and adapt to that; obviously you cannot see the opposite (smaller) parts elsewhere that go beyond (s)RGB.

You can submit a feature request,
https://illustrator.uservoice.com/forums/333657-illustrator-desktop-feature-requests
https://illustrator.uservoice.com/

If one is already submitted, you can join it.

[Brad @ Roaring Mouse]

Sorry, this would not be a good thing, not even for offset. This is also why hexachrome died a quick death many years ago. Every machine will have different capabilties and response to these values, so being able to specify them would be nonsensical. Besides, not every wide gamut printer has JUST CMYKOGV and even if they did, their inks would behave differently. It's the use of color management and properly crafted ICC profiles that determine consistent output, not to mention a good operator at the wheel. 

[Jacob Bugge]

Thank you for the clarification of the killer facts, Brad.

It would have been nice to be able to get at least some impression of the possible colours while working on them as for CMYK.

I was aware that it would be a difficult/impossible task to realize such a feature.

[Brad @ Roaring Mouse]

Yah. The printer I was working with at the time had me explore outputing Hexachrome (essentailly CMYKOG) once we bought a 6-colour press. It didn't improve things enough for our clients to accept the higher cost to run, so it died quickly. Color management was a pretty new thing and hard for even my boss to grasp. It didn't help that, at the time, all our colour (drum) scans were already CMYK so were already dumbed down.

[Ton Frederiks]

Although it is a long time ago, 1998, I have some experience with software that could take an image (preferrably RGB) and separate it into any number of colors. ICISS was made by VISU technologies, a part of the van Ginneken & Mostaard group, a prepress company in the Netherlands. It could separate to all kinds of output, newsprint, Hexachrome and HiFi color.

The software was not cheap and dongle protected.

I helped writing the manual and also gave some training to resellers and customers.

Cees Spronk and Oscar Rysdyk who wrote the sofware had also made some Photoshop selective color correction plug-ins; CoCo.

Later the ICISS software was licensed to Pantone, who did not a very good job of promoting it.

Like all high end prepress companies with expensive equipment, they had a hard time surviving with the competition of Photoshop and powerful, relatively inexpensive, computers. They even helped to make Photoshop finetune the separations for the European market by making press proofs with European inks that Thom Knoll used in Photoshop (before Color Management took off). Later I heard that they hesitated to do that, knowing that it was a matter of time that Photoshop would become a fierce competitor.

[Bobby Henderson · Accepted solution]

In large format printing I most often see Light Magenta and Light Cyan added to the basic CMYK ink colors. There may be large format printers to do CMYKOG, but I can't think of any immediately. White ink is a big deal with newer large format printers. "Sandwiching" layers of white ink and color really helps any print that will be back-lit.

But, yeah, processing six color print jobs really needs to be managed by the RIP. I don't like designing print-related work in RGB. Sometimes there isn't any other choice. Printers with additional ink colors can simulate Pantone spot colors a good bit better than a straight CMYK printer.

[Brad @ Roaring Mouse]

"There may be large format printers to do CMYKOG"

There are many.

In fact, my own printer (an HPz3100) has even more: it has 12 inks in total, which include M (Magenta) Y (Yellow) PK (Photo Black) G (Grey) LG (Light Grey) LC (Light Cyan) LM (Magenta) R (Red - which is really more of  deep orange) G (Green) and B (Blue - richer and more vibrant than Cyan), along with a MK (Matte Black) and a GE (Gloss Enhancer).

(The extra Blacks and Greys are mostly for superior full-range B&W photo printing, but are also used for full colour work)

It's imperative that this be a color-managed workflow and requires RGB data to take advantage of the wider gamut.

(You will notice there's actually no Cyan – Between the Blue ink and the Light Cyan ink, it covers everything a Cyan would do, so it is unnecessary.). I typically send AdobeRGB data and it's gorgeous.

Also, for my design work, the extra inks allow me to print more than 90% of the Pantone library accurately, whereas a typical CMYK printer can barely handle 20%.

In these printers, the "Light" inks are there to alleviate the problem with sthe catter-dot process an ink-jet uses, as the inkjet "dots" are a fixed size, so at the light end of a color gradient (say between 0-5%) theses dots are very obvious and far apart, so the light inks "fill things in" for a much smoother result.