Known Participant

Question

Rich Black for Black and White Photographic Images?

Forum|Forum|1 year ago
February 4, 2024
4 replies
5119 views

I'm currently working on printing a zine containing some of my black and white photographs. I printed a test zine with the printing company I'm working with and the images look dull and flat - no deep blacks to speak of. The zine was printed on a digital press and I used the CMYK color profile provided by the printing company (Coated GRACoL 2006 (ISO 12647-2:2004)) in my images/InDesign file.

To remedy the lack of deep blacks, the printer suggested that I use Rich Black (CMYK = 30% 30% 30% 100%) rather than Standard Black. I understand how to create a Rich Black swatch in InDesign and apply it to something like a solid black background, but I don't really understand how to apply that swatch to my photographs.

Can anyone suggest how I might go about using the suggested Rich Black to produce deep blacks in my printed photos, using InDesign and/or Photoshop?

Thanks in advance.

Scott Falkner

Community Expert

I suggest a duotone or simulated duotone instead.

https://www.adobe.com/ca/creativecloud/photography/discover/duotone-effect.html

rob day

Community Expert

but I don't really understand how to apply that swatch to my photographs.

Hi @achasin , I’m assuming by black and white photos you mean you are placing Grayscales?

As long as the placed grayscales have no transparency, you can Direct Select the image and apply any color or Swatch. If you turn on Separation Preview you can view the output values when you mouse over the image.

By default a placed grayscale with no transparency gets the [Black] Swatch applied. Here Separation Preview shows the output of the 100K patch in my control ramp as 0|0|0|100. You might check the black point of your grayscale images and make sure your black point is really hitting 100%—that could be the reason for the flat grayscale output:

The middle image has my Rich Black Swatch applied 65|50|50|100. Note that usually you want there to be some extra Cyan in the mix if you want a neutral gray:

Also if you assign an RGB black the conversion to CMYK on Export will be to the blackest black point allowed by the GRACoL profile. Note that the RGB black has to be something more than 0|0|0 in order to force the conversion:

A

achasinAuthor

Known Participant

@rob day Thanks so much for the reply.

Showing my ignorance here, but when you say 'placing Grayscales' I assume you mean importing Grayscale images into InDesign and placing them onto a page, correct? The process I followed (which may not have been the best choice) was to take my original RGB image files, convert them to CMYK using the printer's supplied profile, and then insert them into my InDesign document. So they weren't Grayscale images when I brought them into InDesign. I have my RGB originals and I can convert them to Grayscale first before applying the Rich Black swatch, if that's a better option. Or does explicitly selecting the Rich Black swatch for a CMYK image also apply the swatch?

Re: the black point, what is the best way I can check to see if it is hitting 100%? I tried to use the Curves panel in Photoshop to check this and the deepest blacks did show up in the clipping preview, but I didn't see a way to view the black point as a percentage. Again, showing my ignorance of Photoshop here.

One more silly question about the way Photoshop applies these swatches - if I create a Rich Black swatch (for example) and select it after direct selecting the image in my InDesign document, what is the algorithm used by Photoshop to apply it? i.e. which values in the image are replaced with Rich Black?

Thanks again for all your help.

rob day

Community Expert

To follow your printers suggestion of applying a rich black swatch to the image, it would have to be done to a placed grayscale in InDesign—you can’t apply a color swatch to an RGB or CMYK image.

Can you share an example of your original RGB image and the converted CMYK image you placed in InDesign? Also, did you supply the printer with a PDF? If so, can you also share the PDF?

Derek Cross

Community Expert

Maybe worth posting in the Photoshop forum.

James Gifford—NitroPress

Legend

I think @rob day is the go-to user here for this issue.

It's been a while since I did high-quality offset work, but I think images have to be prepared for rich black output — I am not sure if simple export from InDesign will remap the colors from image files. But I could be wrong; I know the PDF export process has endless levers for this kind of control.

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