Embedded RGB SVGs - how to convert to pure black (CMYK 000x)

[p10n]

I have created business cards in Affinity Publisher. The cards all contain QR codes that I had created with a command-line tool, and dragged them into the AP document, so they are now embedded. About 35 in total. The QR codes are dark grey.

Now for offset printing, my printer shop recommended to use plain black instead of composite black, to avoid unwanted color effects if a color shifts a bit during printing.

My document is CMYK / Coated Fogra 39, so I can nicely use, e.g., 0-0-0-70 grey for all text, but the embedded SVGs still produce composite grey, because they are RGB internally.

Is there a way I can change the color of all embedded SVGs to CMYK 0-0-0-70, other than manually touching each of the >35 SVG files?

A workaround I found is to apply a "color overlay" from "Effects" with "brighter color", and choosing a lighter grey (0-0-0-61) than what the RGB conversion would yield. This seems to do the trick, at the cost of being forced to use a lighter gray. And it does not look like a reliable solution to me.

Is there any better option I have?

(I looked at resource manager, but the single button that is not disabled is "Replace". Which means I would have to re-create the SVGs in CMYK and re-embed them, I guess.)

[lacerto]

If your document is all gray (no colors), place all elements in a Gray/8 Publisher file (having D50 as document color profile), then find replace all your K70 text and replace it with Gray 30 text (using 100% scale). Then export to Gray ("Document Color" and "Document Profile"), and do not include ICC Profile. Your texts will be DeviceGray 70% and QRCodes, as well (or equivalent gray they were initially created in). You could start also with an RGB document and export to Gray to achieve the same (if you have raster RGB images, you would need to force image space conversion at export time).

 

 

(You could similarly produce K100 QR codes and text, but I was assuming that you specifically wanted to have K70 level.)

 

[p10n]

Thanks for your reply, lacerto, and for the very good video, obviously a clean systematic solution!

Though, my document has color elements as well. (It is just the QR codes and some parts of the text that are grey.)

I guess I will just click trough all of them, and take the learning for next time.

 

[lacerto]

On 4/7/2025 at 4:04 PM, p10n said:

Though, my document has color elements as well. (It is just the QR codes and some parts of the text that are grey.)

Here is an interesting workflow to try to work around that, so that you can have ICC-based RGB raster files included in a mixed color mode PDF (no forced image color space conversion), while having RGB-based vector format SVGs (with rich black QRCodes), and Grayscale defined native text exported as DeviceGray elements (basically K components when producing in CMYK). So while your work and export color space seems all gray, you can actually pass through color and still handle grays as K elements:

I am not sure what your printer might think of this, whether the DeviceGrays would actually stay K-only when this file is ripped or be converted to rich black, but it might be worth a try! Anyway, if it works, it would save you the trouble of converting those SVG QRCodes to K-only CMYK EPSs or PDFs (which you might be able to do in a batch using e.g. Designer Export Persona, so not necessarily a big thing; and if you do that, you can have colors handled in a standard way without needing to perform these kinds of hacks).

mixedcolorgray.afpub

UPDATE: I ran a couple of prepress routines on Adobe Acrobat Pro for the mixedcolor mode (DeviceGray + sRGB images) PDF produced from Publisher (as shown above), and could create a PDF/X1a:2001 compatible file (retaining the DeviceGray, but converting sRGB to DeviceCMYK). This basically shows that this production method, while probably not "by design", should be fine for production (with some reservations as for flexibility of the printshop).

mixedcolors_fixed_pdfx1a.pdf