How to color manage a job printed on off-white paper?

[MarieMeyer]

I've been asked to do a book design. The print run is will bee 500-1000 copies, so it will going to go to a short run press. It has color graphics and photos. The client doesn't want bright white paper - he's asking for "off white or cream". 

How do I do color management in this case? I've done books in 4 color before, using the GRACoL print condition and was delighted with how well the final product matched my expectations. But in those cases we used bright white, recommended by the printing company because it matched the GRACoL profile. 

I'm using CC on a Mac, mostly InDesign and Illustrator, with some Photoshop.

[NB, colourmanagement]

Hi,

so that you can preview (softproof) the result properly you need an ICC profile for the actual paper the job will be printed on, ideally

I hope this helps

if so, please "like" my reply and if you're OK now, please mark it as "correct", so that others who have similar issues can see the solution

thanks

neil barstow, colourmanagement.net :: adobe forum volunteer

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[rob day]

The client doesn't want bright white paper - he's asking for "off white or cream".

I agree with Neil a custom profile from a target printed on the cream paper would pick up the affect of  the paper color on the process inks, but I’m guessing that won’t be realistic.

On thing to note: InDesign’s built-in [Paper] swatch has an affect on the preview of placed images and native color when Overprint or Separation Preview is turned on, but does not change the output values. So, if you could get a Lab reading of the paper, you could at least set the ID [Paper] swatch to match the paper color.

Here I’ve set [Paper] to pink so it is easy to see the affect:

With Overprint on the [Paper] color affects the soft proof without changing the output values

Of course this doesn’t help if you want to make a color correction based on the paper color’s affect.

It looks to me like InDesign simply multiplies the image to the [Paper] color when OP is turned on, so you could consider using a background layer in Photoshop with the imagery above multiplying, but you would have to be careful not to include the background when you save.

[Gusgsm]

I have done that and, unable to do an ICC profile for the paper, the approach was getting a Lab reading of an unprinted paper of that stock (ColorMunki spectrophotometre did the job all right). There are somecaveats:

1. This is repairing an engine with a band-aid. The proper way would be doing a real ICC profile. So, though it is much better than "none", it is just what it is.

2. When reading the Lab values, try to make a batch of readings and then make a mean value (you'd suprise yourself with the quite differents values you'll get with El Cheapo papers).

3. When reading, do not read papers which are printed in the other side and try to make a stack of them (remember you don't need whole sheets, a stack of tiny pieces can do).

4. I'd not use "multiply" for the layer that Rob Day suggests (though it is the obvious approach), I'd use "Darken" mode. Just give it a try and decide yourself.

5. As for "proof colors"... Best luck, because you'll be using an ICC profile in any case (a similar one would be a wise choice) and then you may or may not use "simulate black ink" (quite likely) and "Simulate paper color" (not so much likely), just for softproofing on screen.

In any case, Have you asked the print house if the have an ICC profile for that particular paper? Sometimes Xmas comes early and not all printers live in the past.

[rob day]

I'd use "Darken" mode. Just give it a try and decide yourself.

I think InDesign is Multiplying for the Overprint Preview because Darken would only affect image colors that are lighter than the [Paper]’s Lab value, so unless the sheet is darker in value than the image highlights there would be no proof effect.

Here the only affect Darken has is on the nearly white highlight at #2, the other samples don’t change.

Multiply has a some affect on all of the color—if the paper is creamy enough it might affect a color like 20% Cyan, which Darken would not show:

If the paper color gets darker than the image highlights, Darken mode just obscures the highlight detail without affecting the rest of the image.

[MarieMeyer]

Three very helpful responses, thank you all.

Can you help me walk through this?

Let's say the printing company uses the GRACoL13 print condition for everything, even when the paper stock isn't the correct whiteness.

Let's also say I can get them to print a batch of targets for me on cream-colored paper so that I can make my own profile for the purpose of proofing.

I then send the job to them and they print it with the GRACoL 13 print condition. Do I get what I expected, or does the profile conflict cancel out all the judgment calls I made?

[rob day]

Let's also say I can get them to print a batch of targets for me on cream-colored paper so that I can make my own profile for the purpose of proofing.

Do you have the hardware and software needed to make a profile?

To use a custom profile you would have to assign it as your InDesign document’s CMYK profile, and convert any RGB images into that CMYK space. The conversion to the custom CMYK space could happen in Photoshop, on export to PDF via the Output tab’s Destination setting, or at output by the printer. If you are providing a PDF with RGB images, the printer would need to have the custom profile, and be willing to use it in order to make the conversion at output. If you are providing an all CMYK PDF you would need to comunicate with the printer that you don’t want them to make an additional conversion into their GRACol 2013 profile—there are alot of variables to control.

One thing to keep in mind about offset printing profiles—offset is a variable process so press profiles can never be completely accurate. The profile of a press might change during the run if any of the ink densities change. Unless the paper is really different than white you might be over thinking things. Will the printer be providing contract proofs? If you are worried about subtle color make sure you get proofs.

[MarieMeyer]

Contract proofs - another complication! Because of course they are premised on a certain white stock, aren't they?

[rob day]

Talk to the printer. The proof would be color managed to imitate the press color, so they may be able to account for the paper color.

[Gusgsm]

"Contract proofs - another complication! Because of course they are premised on a certain white stock, aren't they?"

Well. Aside from a particular case like this —where there is no real colour management (no ICC colour profiles) but there is a good hearted try to achieve a reasonable match of what is going to be printed— a "contract" proof is not a complication for the client (you), but a safety net. Even more, if the proof is a "certified" proof accepted previously by all parties in a contractual form, the final printed results should match colorimetrically the proof with a tolerance defined previously. All this is facilitated a lot nowadays by international standards. So you and printers and providers don't have to invent the wheel every bloody job.

If nothing of this has been set and signed, all words used are just that, nice words (even in good faith) and the so-called proof would be a pretty printed paper but it won't be a "contractual" proof.

But fortunatelly this is going to the extreme, usually, because good printers that are approached in good faith and work fine will do their best to achieve quality.

But I would not do a work like this (or in general) with no colour proofs (even if they are not really "contractual"). It's a very bad idea.

[rob day]

Also, rereading your post—it’s a short run press. If you are anxious about the color why not run a press proof of some sample pages?

[D Fosse]

As long as the paper color isn't too extreme, the standard way to deal with this is simply to calibrate your monitor to a visually matching white point.

Then just work normally. What you see is what you get.

[rob day]

You mean you would start switching monitor profiles depending on the press sheet color?

[D Fosse]

Yes, absolutely, I do it all the time. If I have a sample of the paper certainly.

Switching monitor profiles is just a single click in Eizo Colornavigator. You can have as many profiles as you want, and return to your standard profile when done. I believe NEC Spectraview can do the same.

Obviously you can't do that with dyed paper, but stock paper color, no problem. Equally obviously I'm assuming a CMYK profile specified from the printer.

If the print profile provided has the paper color built in (IOW white does not remap to white), then the question is moot. You just proof to it.

[Bob_Hallam]

The most accurate and efficient way to do this is in the ICC profile dor the destination color space in Absolute Colorimetric rendering intent.  Just changing the white point of the profile can work but is not optimum. Having an ICC profile to use in color settings for the paper color of specialty jobs is an easy workflow.  Recalibrating a monitor is time-consuming, so that's a workflow trade-off I'm not willing to make.  If your monitor white point is set up to match the whitest paper in your workflow, with the corresponding ICC profile for that paper proof, tweaks from there are easy by changing the ICC destination profile.

The downside of adjusting a monitors white point and also editing the white point of the destination profile is that it is an artificial simulation of what "might or could" occur in a proof or print process.  Color quality first I'd choose the white point edit in the destination profile.   For the most accurate work profile the actual print process.  Extremes in white point adjustments don't always show how some colorful papers affect other colors in that print process.  

[D Fosse]

It all depends on how off white the paper is.

Calibrating your monitor to a different white point is not particularly time-consuming, especially if it prevents very time-consuming trial and error later on.

Again, this is standard procedure. I've been doing this for every major book production for years, and it works. It's a very efficient way to align what you see on screen to what comes out of the press. It eliminates uncertainties and lets you work with confidence. What you see is what you get.

It's not just the white point. Perhaps even more important is the black level and maximum ink. The contrast range determines the overall "punch", and a weak black level in print is responsible for most of the myth that it's impossible to match screen and print. Adjust black level on screen, and you can get an almost perfect preview of the finished print.

As I said, all this assumes a standard print process using a more or less standard CMYK profile (one that maps document white to 0-0-0-0).

Of course, you do need a good monitor with dedicated calibration software that can do this easily. Basically, that's an Eizo Coloredge or an NEC Spectraview. Dells and BenQs and Asuses can't do this, nor, for that matter, an iMac. But this is why an Eizo/NEC is worth the cost.