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C
calebp32525708
Participant
February 29, 2016
Question

CMYK Pre-Press - Rich Black v Gray Scale printing

  • February 29, 2016
  • 1 reply
  • 2034 views

Hi Folks:

So just to be upfront, I am a bit new to pre-press production and the use of CYMK in the printing process.

I have a publication that has a color cover and B&W(Grayscale) internal pages that we make and layout ourselves using InDesign. Within InDesign, using the Separations Preview, I have everything set so that the only color is on the cover. All internal pages are B&W/Grayscale. (I can prove this using the separations preview. Disabling the K shows that all internal pages go blank).

I have taken a "high quality" print output PDF file of this publication. THis PDF also shows that the internal pages are B&W (gray). Using Acrobat Pro's Separations preview, disabling K shows that all internal pages are white.

So here's the thing:

When I print to a Konica Minolta C364e using Acrobat pro, each internal page is costing me a color click and is being done using CMYK, not K. The only way I can get internal pages to NOT print in CYMK is to tell Acrobat Pro to "print as an image" at 600DPI. Then the internal pages print K-only.

This is driving me nuts. I used preflight tools to 'convert document to grayscale' and printed an internal page, and it still costs a color click prints using CMYK.

I'm besides myself why the internal pages, which are defined as K-only, are printing out as Rich Black.  And I can't tell which is the culprit: Adobe Acrobat or a printer driver setting. I know they are inter-twined. But somewhere, something is telling the PDF to go to the printer and come out as a full CYMK document, rather than a CYMK cover and K-only internal pages.

(Also, in addition to 'print as an image', I can also put a check in the box "print grayscale" in acrobat which does properly print the internal pages as grey (K-only) clicks. But it also prints the cover as grey.)

I honestly can't figure out where the printing is being translated to Rich Black for internal pages.  It's driving me crazy.

This topic has been closed for replies.

1 reply

Dov Isaacs
Dov Isaacs
Legend
February 29, 2016

This particular printer model supports output to emulations of PCL, XPS, and PostScript (i.e., not Adobe PostScript). Depending upon which driver you are using, you may be using either the PCL or XPS emulations instead of the PostScript emulations. Only output of PostScript to your printer can guarantee pure grayscale instead of rich black / rich gray.

Check what driver you are really using and if not for emulated PostScript, install and try printing to that instead.

            - Dov

- Dov Isaacs, former Adobe Principal Scientist (April 30, 1990 - May 30, 2021)
C
calebp32525708Author
Participant
March 1, 2016

Good morning, Dov:

I normally use the Postscript driver, and did so in this case. However, I also printed to the PCL driver with the same results.

In Adobe Acrobat, I even went into the Advanced option and told it to preserve Black, Black and Grays using the K channel.

I've tried "Adobe Manages Printing" and "Printer Manages", both with the same result.

The printer driver (PostScript) is set to "AutoColor".  It is the latest PS driver from Konica.

I understand in many cases, folks would actually want Rich Black as it can make your darks far superior. For us, a color click costs several magnitudes higher than a black click. So to not get this right actually puts us in a position of losing money on the print job.

I've got to figure this out. I spent so much time ensuring that the pages contained the right color spaces and colors to ensure the internal pages are K-only. All my objects that are placed and generated, from Adobe Illustrator, to Photoshop files (gray scale) to InDesign files have internal page elements on the K-channel only.

I know using the separations preview that the PDF is using the channels properly. It's just in the rendering. And as I said above, I cannot tell if it's Acrobat or if it's the printer.

Do you have any other ideas on what I could try?

Dov Isaacs
Dov Isaacs
Legend
March 1, 2016

Unfortunately, I understand the problem you are facing all too well!

I was actually the person who instigated putting in the Treat grays as K-only grays, Preserve Black, and Preserve CMYK Primaries options into the Advanced Print Setup of Acrobat Print. We did this specifically to handle situations in which R=G=B colors or CMYK=(0,0,0,k) conversions to CMYK=(c,m,y,k) caused what appeared to be monochrome pages to print with multiple colorants. And for Adobe PostScript printers we tested, this does indeed work.

That having been said, printer manufacturers often put in their “secret sauce” color management such that what you think is supposed to print as a specific CMYK value actually prints with some modified C'M'Y'K' value.

I would try changing the printer setting in the driver from “AutoColor” to either something like SWOP emulation or even better, if they have it, a “color unchanged” (or effectively “don't f*ck with my color”) mode! See if that helps.

              - Dov

- Dov Isaacs, former Adobe Principal Scientist (April 30, 1990 - May 30, 2021)
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