Black changing from 100% to 91% when printing to PDF

[edwardp70705052]

Hi. I discovered yesterday – from a client's production department – that the text in the PDF I'd sent wasn't 100% black. Puzzled, I checked my settings and they were all exactly the same as I've used many, many times; I also checked that all the text in the layout was definitely black (it was).

I then started tracking back through previous jobs, checking the text with Acrobat's output preview, and found that all the PDFs generated before 20th June (or thereabouts) had 100% black text, but the ones after this date are 91%. 

I want to stress at this point that I didn't change my usual settings at any point, so I assume something changed during an update in the software.

I couldn't find a solution online, so I played around with the settings and instead of specifying 'Composite Gray' in the output tab (as I've always done), I tried 'Composite Leave Unchanged' instead. This resulted in a PDF with 100% black text. 'Export', rather than Print, also worked.

I typeset books and thankfully haven't had any bad feedback (so far) from clients re. the post-June jobs, but it's really worrying that a retty major change can occur in the background.

Maybe it's a bug? I'd be grateful if somebody could throw light on some possibilities.

Thanks.

[Lukas Engqvist]

Use separations preview to track/measure the black both in InDesign and in Acrobat. I suspect Transparency flattener set to RGB or document CMYK is not the same as output CMYK, Use PDFX standards to make sure that the exported colours are also the output Intent. Colour managemet may convert so that a black in one output intent is mapped to a lighter tint in another output space. There is not enough specifics documented here to help in a colour managemnet situation.

[Lukas Engqvist]

You can also check this thread and see if that is the issue you are facing (As primarily working in print I prefer acurate blacks and measure them)
https://community.adobe.com/t5/indesign-discussions/printing-indd-to-composite-grey-pdf-100-black-tu...

[edwardp70705052]

Hi Lukas.

Thanks for the tips and I'll certainly try the Rich Black route. I had already found a workaround, but it's good to have another option (maybe I should have been doing that all along).

I've used the same workflow/settings for a long time and all the PDFs pre-June have 100% black text in output preview, so I worry that something changed in the background in June without my realising.

I guess I'll need to be more vigilant!

Thanks again.

[rob day]

I played around with the settings and instead of specifying 'Composite Gray' in the output tab (as I've always done), I tried 'Composite Leave Unchanged' instead.

Hi @edwardp70705052 , Sounds like you are using the Print dialog to save a postscript file—the Export>Output tab doesn’t have a Composite gray option. If you use File>Export... with one of the default PDF/X presets there would be no conversion of your 100% [Black] values, they would export unchanged as 0|0|0|100.

If for some reason you have to Print your PDFs, set your Appearance of Black Printing Preference to Output All Blacks as Rich Black as the thread Lukas posted suggests, or asssign a CMYK profile that defines black as absolute, e.g. the legacy Photoshop 5 Default CMYK. The conversion from the default US Web Coated SWOP CMYK profile to grayscale would produce the 91% value because with the SWOP profile 0|0|0|100 black is displayed as a lighter value than 100|100|100|100 black.

[edwardp70705052]

Hi Rob.

Thanks for getting back to me, and I will try the Rich Black suggestion.

I had already found a workaround, though, and my main concern was how
something had changed in the background, which affected the workflow I'd
always used (several hundred books) without my realising it.

What you've said makes sense, but the PDFs pre-June are all 100% black,
using the 'Composite Gray' option, and this is the part I don't
understand.

I'll feel the need to check each press-ready PDF before sending now,
which isn't a huge problem, but it would be nice to know what caused the
change.

Thanks again,
Ed.

[rob day]

The conversion from 0|0|0|100 to Grayscale would vary depending on the document's assigned CMYK space, and your Appearance of Black preference--those are document level settings.

Also, you shouldn't need to print the PDF, if you need a Black only PDF, the PDF/X-4 preset lets you choose a Gray Destination profile, or you can use Document CMYK and the printer can output just the Black plate.

[rob day]

Maybe it's a bug? I'd be grateful if somebody could throw light on some possibilities.

Also, color management is consistent in all of the Adobe apps, so you can see why this is expected behaviour and not a bug by using Photoshop’s Convert to Profile... to check the affect of profiles on a CMYK-to-Grayscale conversion.

Here’s a CMYK document with 0|0|0|100 black only on the left, 100|100|100|100 on the right, and the Coated GRACoL 2006 as the source profile assignment. The conversion of black only CMYK to Dot Gain 20% Gray is 93%—0|0|0|100 CMYK is a different color than 100|100|100|100:

If I change the CMYK profile to Uncoated GRACoL, Black only converts to 90%:

With the assignment set to the legacy Photoshop 5 Default CMYK, both conversions are to 100% because the old 90’s curved based profiles did not distinguish Black from Black + CMY:

[edwardp70705052]

Thanks Rob.

You've given me a lot to think about! I've never really given any of this much thought, to be honest, as I haven't needed to.

I've simply used the 'Composite Gray' option for years with resulting 100% black, which now doesn't work, but 'Composite Leave Unchanged' does – so, in my mind, something changed in the background. It was probably lazy on my part, but it did work, with no complaints from any pre-press departments or printers.

You've made me very aware of the complexity of profiles, though, so I'll aim to improve my understanding and make changes.

I really appreciate the time you've spent on this, so thanks again.

[edwardp70705052]

Just to let you know, I think it was the 'Appearance of Blacks' setting that was the culprit in my case.

I'm working in InDesign 2023 and it was set to 'Output all blacks accurately' which I've now changed to 'Output all blacks to rich black' and black is now 100% in the resulting PDFs, using the 'Composite gray' option.

I definitely didn't change the black setting (I wasn't aware of it!) but maybe an update caused it to default to 'Output all black accurately' – I don't know. Checking InDesign 2022 (which I still have installed), it's set to 'Output to rich blacks', which would explain why older PDFs were fine.

Thanks again to you both, for your help.

[Laubender]

Hi Edward,

it could be that you updated InDesign from 18.4 to 18.5 on June 20th or a few days before.

And, when I recall this right, with every update InDesign will be reset to the default color management settings.

This could make the difference for new documents you are producing after the update.

Regards,
Uwe Laubender
( Adobe Community Expert )

[edwardp70705052]

Hi Uwe,

I think you're right, and it's something to bear in mind with future updates!

Many thanks,

Ed.

[Laubender]

@edwardp70705052 said:

"Just to let you know, I think it was the 'Appearance of Blacks' setting that was the culprit in my case."

Ah! Did not see this before my last reply.

How did you currently set it? How was it set before?

Regards,
Uwe Laubender
( Adobe Community Expert )

[edwardp70705052]

Hi Uwe,

I don't recall ever setting it, to be honest, and I've been using InDesign since around CS5.

I guess it must have been set to Rich Blacks as the default, but maybe that's changed now?

Ed.

[rob day]

Is your printer asking for the text to be grayscale? Any Export with the Output Destination set to Document CMYK would leave [Black] text unchanged. The Appearance of Black preference only comes into play when the Destination is set to an RGB or Gray profile.

[edwardp70705052]

No, I don't recall a printer (or production department) specifically asking for it, it's just the way I work and we get used to things, don't we. My clients are publishers (mainstream, with their own production departments), so I don't deal directly with printers.

Some books have integrated illustrations and what's been made clear to me with various production departments is that they don't want RGB images (or any RGB colour swatches) included in the final PDF; images are always supplied to me as RGB (without fail, even if they're black and white line drawings) and I always have to convert them, so perhaps I started using the 'Grayscale' option as a belt-and-braces thing.

As you've probably gathered, I'm not an expert in colour management, so all I can say is I've produced hundreds of books with this workflow and there's never been problem flagged up to me, so I've stuck with it. I'm usually too busy just trying to get the work done, to be honest, and as I'm not an expert it'd be a bit foolish to try fixing something that wasn't apparently broken.

[Rishabh_Tiwari]

Hi @edwardp70705052,

Thank you for reaching out. In addition to the suggestions shared above, I found a similar discussion you can refer to. Please update the discussion if you need further assistance.

Thanks

Rishabh