Combination of color and grayscale content

[Stavre0D4C]

Hi,

I'm working on a project destined for print that includes both color and gray images. My workflow is RGB. There are no color and gray images placed on a same page. Can you tell me, please, what would be the best way to do this?

a) Exporting a PDF from Indesign without color conversion (the resulting PDF is RGB) and then using Adobe Acrobat to convert the color pages to CMYK and the pages that are supposed to be in grayscale to some gray profile. The problem here is that I don't know which grayscale profile to pick: Dot Gain %, sGray etc.

b) Exporting from Indesign without color conversion and then using the Acrobat plugin Quite a Box of Tricks to convert some pages to CMYK and some pages to grayscale. But in this case, I'm not sure which grayscale profile is used within this plugin. If you are not familiar with this plugin, is there a way that I can identify the profile by inspecting the resulting page in Acrobat?

c) Converting all the images to CMYK or grayscale in Photoshop and relinking them to Indesign. No color conversion at PDF export. But in this case, I still have to choose a grayscale profile in Photoshop and I don't know which (sGray, Dot Gain % etc.). I can simply use the one that is set as a "factory default" in Photoshop, but I don't know how smart is that.

And there are other things that confuse me:

- If, say, you export the PDF with color conversion (e.g. to FOGRA or US SWOP or smth), will this affect the grayscale images in the document in some way or they will be left alone?

- Some printshops required from me: PDF/X-3:2002, Acrobat 4 (PDF 1.3), I assume because they don't want live transparencies and maybe for other reasons. When exporting PDFs to this standard you must specify Output Intent Profile Name: [name of the CMYK standard], Output condition identifier: [name of the CMYK standard] and some other things. Now comes the same question, will this affect the grayscale images in some way?

Thank you

[Eugene Tyson · Accepted solution]

Your grayscale images should be grayscale.

And your other images can be whatever colour mode they are.

Export your PDF and either choose to convert it to a CMYK profile (if you know which one)

If not - leave it as No Colour Conversion.

Talk to your print provider. Specify which pages are to be grayscale and which are colour. 

InDesign will convert images to CMYK using the same method as Photoshop.
So there's no need to convert your image colour mode (unless you're colour correcting images) in photoshop. Just place them as they are.

Talk with your print provider. They will help you.

[rob day · Accepted solution]

Hi @Stavre0D4C , when Overprint Preview is turned on, placed grayscale images display as if they are on the CMYK black plate—the document’s CMYK profile and your monitor profile are used for the soft proof of the black plate and grayscale.

Grayscales will also export unchanged to the CMYK black plate as long as the export destination is to Document CMYK or Color Conversion is set to No Color Conversion. If the export is to a CMYK Destination that conflicts with the document’s CMYK assignment, grayscales will get converted to 4-color CMYK.

Photoshop lets you load a CMYK Black Ink profile for making conversions to and editing Grayscales, so ideally you should load the proper CMYK profile for the job and use its Black Ink profile for making conversions and color correcting grayscales in Photoshop.

Load the CMYK profile as the Gray profile—Color Settings>Working Spaces>Gray>Load Gray...>choose CMYK profile

The grayscale soft proof depends on the accuracy of your monitor profile and the CMYK Black Ink output profile—both profiles are used for soft proofing.

More on Black Ink conversions here:

https://community.adobe.com/t5/indesign-discussions/greyscale-jpegs-or-psd-images-are-going-much-dar...