Conversion from RGB to CMYK press ready of a problematic image

[GaudiumMagnum]

I'm trying to convert an image from RGB to CMYK for press.
The conversion has some troubles as image use a lot of colours out of gamut, and also i need to convert to a 300% total ink CMYK profile (such as ISO coated v2 300).

I'm not satisfied with Photoshop conversion from Adobe RGB to Iso coated v2 300 (this is the common profile used by some media partners)... do you have any hints or suggestion?
I know that is quite impossibile to obtain the same vivid and brilliant colours.

I attach the "problematic" piece of image.

[Mylenium]

You will probably have to split up the channels and re-compose them after tweaking them individually. And yeah, spot colors would definitely help.

Mylenium

[GaudiumMagnum]

Thanks

Unfortunately... i don't think spot colours should be available, as we are talking about standard offset print with simple process colours (at least 4-5 different media, so i have to think to the worst scenario)

Which kind of manipulation do you take into consideration for single channel tweaking?

[D Fosse]

There isn't a whole lot that you can do. Remember, you can't exceed 300% total ink!

Keep your info panel up, with a readout for total ink. Then try to push ink coverage as far as you can without going over.

[JonathanArias]

are you doing a layout in indesign? why not just place your RBG image in the layout, and let indesign handle the color conversion when it created a .pdf for printing?

[GaudiumMagnum]

mmm... yes i'm working with InDesign.
I need to output a PDF/X-1a with ISO Coated v2 300... do you think InDesign works better on colour conversion than Photoshop directly? ... or Distiller from .ps file with an RGB image linked...
I have never tried...

[JonathanArias]

i let indesign doing all of my color conversion. i place RBG mode images from photoshop. or rbg mode vector art. select .pdf for print and have indesign handle the color conversion.

you can, in the output section, select "to desitination" and select what you want. but i rarely do that even. i just select .pdf for print and let indesign do its thing. 

[c.pfaffenbichler]

i place RBG mode images from photoshop. or rbg mode vector art

That would seem risky if the vector art includes black elements.

you can, in the output section, select "to desitination" and select what you want. but i rarely do that even. i just select .pdf for print and let indesign do its thing.

That sounds unclear …

The indd files itself should always have the proper profiles assigned and when separating on pdf-export the pdf Output Destination should be set to »Document CMYK - …«.

[GaudiumMagnum]

mmm but you don't know exactly before that how the colours will be ... i prefer to work on CMYK directly on Photoshop to correct some issues and troubles related to conversion... but in this case is really difficult to get an acceptable conversion.
Anyway i will try.

[JonathanArias]

that is why you print a proof. you should to that anyways if you are working in print.  Just sharing how i do it. i do 600k worth of printing a year. and i don't go back and forth converting from photoshop. i let indesign do my color management.

[jessicalaurelkane]

If anyone's still reading this, I have to say, I think this is great advice. I'm new at this and have spent thousands of hours illustrating a 120 page book of children's stories so I want it to look as best as it can. And I read the indesign secret of just letting indesign convert to cmyk, and i have also conversely heard from tons of other people that it's best to convert in photoshop. So I have done my little experiments and for my work, letting indesign do it does look better. Strangely, if I print cmyk directly from photoshop, it looks the best, but I can't figure out why the images printed from indesign look slightly darker. And no, i have not used the adobe bridge to streamline my settings but they are the same from what I can tell. So all in all, my tests show that for me, converting to destination CMYK in indesign looks the best. (Converting to destination does look better for me than using no destination.)

[JonathanArias]

thank you.

[c.pfaffenbichler]

Watch out for banding.

Do you have the layered RGB File in 16 bit?

[Norman Sanders]

Since you are constrained by a total ink % limit and not being able to use touch plates or (I assume) varnish, there is one other element that can have a significant effect on contrast, density range and color brilliance of the process colors: the paper stock. If a choice is available to you, inquire about very high gloss and cast coated paper availability. They will certainly help.

[GaudiumMagnum]

No ... unfortunately ... we are talking about ADV on magazines, this is the reason for 300% total ink limit. I cannot expect great quality in printing and paper.

[D Fosse · Accepted solution]

First make sure the RGB file is max neutral black 0-0-0. That converts into ISO Coated 78-68-58-94 - that's the blackest black you will ever get in ISO Coated (ECI) 300%. That is 300% coverage, that's a brick wall you can bang your head on.

The spectral colors, from Adobe RGB, will be partly out of gamut in ISO Coated - mostly the yellow-greens and the deep blues. You really need to soft proof this and make the appropriate adjustments. The greens will show blocking-up and banding, and the deep blues will very likely turn purple.

Don't worry so much about total saturation. This won't be seen side by side with the RGB version. Just get it to look good with smooth, even gradients. That's much more important.

[Lumigraphics]

Honestly, I would do two things:

1. Talk to the printer about how they want the file prepared. They may want the ID file and do the separations themselves.

2. Go back to the client and tell them that four-color on cheap paper is going to look awful.

This is going to be out of gamut unless you do six-color and decent coated paper.

As for proofing, do several variations tiled in one pdf and see what looks best.

[GaudiumMagnum]

File has to be sent to main stream media print services which have strict tech speciments (PDF/X-1a, iso coated v2 300 CMYK profile, only process colours CMYK).

I have no choice about paper (maybe grade 5 o 3 coated paper, but i'm not sure), no additional inks, etc...

I will try with some tweaking as suggested... but you are wright... this is going to look quite awful...

[D Fosse]

GaudiumMagnum  wrote

this is going to look quite awful...

That's the wrong attitude. It will not look awful if you do it right. It will look consistent with the nature of the medium. As I said, this will not be compared with anything else. It will stand on its own.

I live in this world. I just finished preparing 250 files for a book, in ISO Coated 300%. Each file is custom prepared for the paper that will be used - bringing out what can be brought out, and compensated for what can't. I had my monitor white point set to that paper color, and the black point set to max ink density for that paper. Then I proofed. I know what'll come out of the press.

People get all hung up on total saturation. It's not important. Good color is about color relationships, not total saturation. Get a color to work with the others, and it'll look good.

[c.pfaffenbichler]

Good color is about color relationships

Indeed, otherwise newspapers printed on uncoated greyish stock would not even need to bother with color images.

[GaudiumMagnum]

You are wright, but this is the right path when you have control over the job.
Consider that this image has to be used in 4-5 different services, with no control (and specs) over paper and no proof, so i have to get a compromise acceptable for ... uhm... some generic coated paper.

Maybe "awful" is not the right term (sorry ... my english is poor), but i meant that i know that i will not get a "spectral color" so "beautiful" as the RGB file. This is the only case which give me troubles in conversion... in different scenario i found relative easy to get a nice conversion from RGB to CMYK, working on colours...

So i undertand that there is no easy way to avoid "blocking-up and banding" (i'm not worried about colours), and that it's necessary correct point-to-point image to get a smooth transition between colours (and also working on colours itself).

[c.pfaffenbichler]

Consider that this image has to be used in 4-5 different services, with no control (and specs) over paper and no proof, so i have to get a compromise acceptable for ... uhm... some generic coated paper.

While some publications indeed do not provide their print specs online the websites for many do feature them, pretty well hidden at times, though, unfortunately. And As a last resort one can usually call up someone at the publisher’s – though if one gets the reply »CMYK« when asking for the print space it’s usually to no avail …

This is where separating placed RGB images at pdf export from Indesign really offers convenience – when one has to provide pdfs for many different print conditions.

In any case using the same separation for newspaper print and magazine print would not be OK.

[GaudiumMagnum]

Fortunately the media is magazine only (no newspaper... for this media they have a different ADV).

[GaudiumMagnum]

c.pfaffenbichler  ha scritto

This is where separating placed RGB images at pdf export from Indesign really offers convenience – when one has to provide pdfs for many different print conditions.

What do you mean exactly?
Which kind of predefinite (or customized) job do you use to export (or distill) PDF with RGB images? Do you leave no CMYK profile assigned for output?

Consider that some media portal require CMYK images to accept the file, and avoid any automated conversion (or charge it) from RGB to CMYK.

[c.pfaffenbichler]

I hardly ever embed RGB images in pdfs, for example to avoid missing banding that might become apparent at separation.

When one places profiled RGB images one can convert them to the indd file’s Color Space when exporting the pdf (Destination: Document CMYK - …).

BY the way: If necessary one can change the Rendering Intent (Object > Image Colour Settings) for individual images in Indesign.