How can I do separations in more colors than CMYK?

[Mart Marend]

In CMYK it is not possible to print all colors correctly, specially not nature photos with flowers for example. I know it is possible to print in more colors like with 7 colors, CMYK + green, orange and wiolet. But how can I manage to make separations for 7 plates? Is there some plug-in for this?

[Norman Sanders]

If you google the term Hexachrome it will provide details about a six-color process (adding Orange and Green) that Pantone introduced via Photoshop about ten years ago.  It was subsequently discontinued.  That leaves you with working with “touch plates” (called “kickers” by some old pros) that are modified versions of one or more of the CMYK plates and run in an additional special color or two to extend the normal four-color gamut.                      

[c.pfaffenbichler]

You may want to consult with your print providers about what they can offer. 

If they offer anything beyond CMYK you might be best served to work in a »large« RGB Space (Adobe RGB, eciRGB v2, …) and let them handle separation. 

I think there may have been a renewed interest in such processes lately but it’s probably primarily relevant for packaging. 

https://www.printing.org/blog/7-things-you-need-to-know-about-7-color-printing

https://www.lifewire.com/4-6-8-color-process-printing-1077448

[Jumpenjax]

Ditto, totally agree with c.pfaffenbichler.

[Stephen_A_Marsh]

Is the job really going to an analogue press? Your printer may not discuss it with you as this is now mostly about price, so they could run the job digitally. If this was the case, the digital press would likely have a wider gamut than standard press CMYK, however, they probably simulate standard press CMYK as a standard target.

Is this a theoretical question or practical?

If practical, do you have a quote from a printer to produce the job as CMYK vs other methods?

[Mart Marend]

It is not a theorethical question. I have printer capable to print in up to 8 colors. My idea is to use CMYK + green, orange and violet to get gamut needed for printing a book on wild orchids. My problem is to find a way to make the separations. I have found that the packaging industry uses 7 color print but their printers are not fo book printing.

[c.pfaffenbichler]

The ability to print 8 colors is not that surprising – to print both sides of a publication’s pages in 4C in one go the press needs 8 units anyway. 

But does the printer have any experience with 7-color-printing? Do they offer separation-services? 

And a side-note: As you seem very focused on color accuracy you may, before printing the whole run, want to see proofs – which may be pointless and it may only be truly reliable to do a small test-run. 

Which may run into a lot of money … 

[Stephen_A_Marsh]

OK, if it is a practical concern, then I'd start with my previous question:

Do you have a CMYK vs. CMYKOGV quote from a commercial printer with the expertise to print such a project?

Do you really need +OGV? Perhaps only adding violet will be enough.

If you have the budget for 7 colour printing, how will this translate into a final commercial product? Will the target market be willing to pay extra, or will you absorb the cost and make less profit?

Run length may help, shorter runs would be too costly for 7 colour offset print, so you may go digital. There may be a wider CMYK gamut available in a given digital press, so it is then a matter of colour management and the best input image would be a wide gamut RGB image. This would need to be planned and tested with care and communication with the commercial printer.

Some digital presses offer 5 or more colours.

It is even possible to use non standard CMYK offset press setups to achieve a wider gamut than traditional CMYK. Don't forget screening, with FM screening may also improve colour in light pastel hues.

But in my opinion, it is all theoretical until you have quotes and are happy that the final printed output meets your vision for a "more lifelike" reproduction of the flowers.

I'd start with the money, that will dictate the technical requirements for image processing.

[Mart Marend]

It's OK with the printing cost to print 7 + 7 colors. We have a good corporation with the printer and in our normal CMYK jobs we never need proofs. I know what I get compared with my monitor. The printing office can not provide the separation service.

OGV is definitly needed. Now I need either a tool for the separations or a service-bureau who can help us. Then we need to make a true life test-run in the printer. So now in the first place I would like to find the tool for separations. Earlier it was possible to make other separations i Photoshop with more colors like Hexachrome in six colors. I do not know if there is possible to find a plug-in for this?

[Stephen_A_Marsh]

Forget Hexachrome, it is dead.

You can create a multi-channel ICC profile with the appropriate ICC profiling software and Photoshop can separate to such a profile using the "Advanced" Convert to Profile option:

This is not something that really works well using "generic" profiles, best results would be for the printer to do a press run using supplied 7 colour profiling targets, then you would measure in the charts and create the profile. If you don't have the software, hardware or knowledge to do this, then I would recommend hiring a consultant to do this for you, so add that to the budget.

[avis42897919]

I tried to follow your advice but the multichannel option is disabled. How can I activate it?

[c.pfaffenbichler]

Could you please post a screenshot with the pertinent Panels (Toolbar, Layers, Channels, Options Bar, …) visible? 

[avis42897919]

This is the required screenshot.

[c.pfaffenbichler]

Did you »create a multi-channel ICC profile with the appropriate ICC profiling software«? 

Or have you gotten one from the print provider? 

[avis42897919]

I tried a profile SC-P9000_P7000_Series_LLK LegacyBaryta_PK_v1 for Epson P9000 that has additional colors, orange and green.

[TheDigitalDog]

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@avis42897919 wrote:

I tried a profile SC-P9000_P7000_Series_LLK LegacyBaryta_PK_v1 for Epson P9000 that has additional colors, orange and green.

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The printer does, the profile doesn't; its RGB. That's all you can feed to an Epson like that. RGB to print driver, print driver then allows printer to use those additional inks. 

[avis42897919]

Thanks, I will look for a real multichannel profile. Can you suggest where can I find such a profile?

[TheDigitalDog]

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@avis42897919 wrote:

Thanks, I will look for a real multichannel profile. Can you suggest where can I find such a profile?

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Find one specifically for what and whose output device? Do you understand that a profile defines a specific device behavior?

Do you have a print provider? 

[PECourtejoie]

And I would add, a specific combination of device, inks and paper... 

[Stephen_A_Marsh]

I tried a profile SC-P9000_P7000_Series_LLK LegacyBaryta_PK_v1 for Epson P9000 that has additional colors, orange and green.

By @avis42897919

This sounds like an Epson device profile, not a multi-channel analogue press profile designed to create separations.

[Stephen_A_Marsh]

I tried to follow your advice but the multichannel option is disabled. How can I activate it?

By @avis42897919

You need to have a multi-channel ICC profile installed and then Convert to Profile - Advanced mode will offer that option.

[Stephen_A_Marsh]

Some links that you might find of interest:

http://the-print-guide.blogspot.com/2009/06/hi-fi-color-8-strategies-to.html

http://the-print-guide.blogspot.com/2009/01/printing-at-dmaxx-maximizing-cmyk-gamut.html

https://www.pantone.com/articles/faq/what-is-extended-gamut

https://www.xrite.com/blog/5-tools-to-print-extended-gamut

https://www.idealliance.org/xcmyk

https://www.idealliance.org/ecg