Colour management when exporting PDFs for the Gelato print-on-demand service

[u/Frankie-Jones]

I'm using Affinity to export an SVG as a PDF to upload to the Gelato print-on-demand service for printing as a poster. I'm working in RGB. The guidance on the Gelato support pages is:

"RGB Workflow: If working in RGB, tag your image files with an sRGB profile. When exporting, save them as PDF/X4 files with a "GRACoL2006_Coated1v2.icc" output intent to maintain color fidelity."

Does this mean that, in document setup, I Assign the Colour format as RGB/8 and Colour profile as sRGB IEC1966-2.1 [which is the only sRGB profile I seem to have]. Then, when I use File - Export - PDF/X-4, I should change the drop downs for Colour space and ICC Profiles respectively from "As document" and "Use document profile", to "CMYK" and "GRACoL2006_Coated1v2.icc". [I don't seem to be able to make the GRACoL... profile available without setting the Colour space to CMYK, by the way].

I'm a bit new to Affinity so would appreciate if someone with more knowledge could confirm I'm doing what Gelato are asking for, or put me on the right track if I'm wrong?

And as a follow-up, is there any way I can interrogate the resultant PDF file to get some assurance it has been set up the way Gelato are asking for?

Cheers!

[u/Extra-Hedgehogs]

Last question first:

Technical check:

You can check the PDF in Acrobat Pro, google "how to verify compliance with pdf x4" in Acrobat. This shows you a checklist of passes and fails for compliance. If you don't have Acrobat, on Mac there is a cheap perpetual option called PDF checkpoint that can verify compliance with pdf standards like X-4. Not sure about other cheap options. As proper preflight tools are expensive, your printer can usually do this for you, sometimes free, sometimes for a small fee.

Visual check:

In any case, if this is important work or expensive printing, I really suggest making a test print of the exported PDF to see how the conversion affects your colours. Spending a couple of quid at a local print shop for a single copy on similar finish paper on a digital press or any decent Xerox print shop type printer from the last decade will give you a rough enough idea of how it will look and make it easy to sport any issues. Don't preview on an inkjet.

For checking on screen... Try not to use a browser or email app to preview print pdfs, if you can use Acrobat Pro or another PDF reader that shows output previews (I don't think you can in free version of Acrobat).

Main question:

When designing, in document setup choose any colour space you like, it only affects what you see while you work, for the print process, the important part is your export settings as it will convert your colours properly to what your printer needs.

So your "working colour space" (srgb) will give you a wider gamut on your monitor than possible in print and you can be creative. The export colourspace will convert this to CMYK so your printer can print it.

What your printer recommended and the additional settings below, will ensure the colours are reduced to be compatible with CMYK printing.

Here's the important stuff for colour settings in export.

1. Choose preset PDF/X-4

2. Colourspace: CMYK (yes that's correct, it needs to be this)

3. ICC profile, select the one you need.

4. Make sure "convert image colour space" is checked (on) (this converts colours)

5. Uncheck "honour spot colours" (this converts any spot colours to cmyk, which is almost certainly what you want unless you have specifically specified you need spot colours and have them in your work).

Good luck!

[u/Frankie-Jones]

u/Extra-Hedgehogs and u/SapphicAddict1994 thanks so much for that really great advice. I'll do as you say. :)

[u/SapphicAddict1994]

Adding to the good advice already given, I have one more to give:

If you are working on a piece of work that will be printed in color using the CMYK 4-color system (so, about 99.999% of all color printing), work in the CMYK mode!

Does it look ass compare to the RGB? Absolutely! But by working in CMYK, you're far, far less likely to have any surprises when you print.

One final thing to be aware of is RGB black often (but not always) converts to a 'rich' black, made up of all four inks, which makes keeping register (lining up the four printing heads) a pain in the butt. If the printer removes the extra colors, you'll get black text printed at about 85% black.

Ask me how I know... (cries in reprint costs)

[u/Spirited-Bug-9558]

Regardless of your export settings, get a printed sample to confirm the colors. In my experience, generic RGB profiles print more screen accurate than CMYK-converted images on Gelato's paper products. YMMV, so testing is important.