04-22-2025, 05:17 PM
Random thoughts:
I've achieved very good RGB to CMYK conversions for printers using Cyan, as a stand-alone application, in version 1.2.4, not as a GIMP plugin. From an example:
The only way I've achieved an unacceptable 99.9% difference between the original RGB and the CMYK tiff is when I use the direct export provided by GIMP 3.0 (without a plug-in). When I open the file in other programs, the tonal differences are quite large. But CURIOUS!: When I open the converted image in GIMP, whether or not you enable soft-proof, it looks great. As if GIMP had done its job well, but the other programs don't recognize it. I don't know why this happens.
Although Fogra emphasizes offset, I prefer Fogra39 over US Web SWOP v2 because it offers far fewer out-of-gamut colors. This can be confirmed within GIMP or Scribus. It also depends on your needs.
Within open source software, another great option for creating a PDF for printing is to use Scribus to generate a full CMYK:
I've achieved very good RGB to CMYK conversions for printers using Cyan, as a stand-alone application, in version 1.2.4, not as a GIMP plugin. From an example:
- Approximately 76% difference between the original RGB and a CMYK *.tiff if I use the Fogra39 color profile.
- Approximately 56% difference between the original RGB and a CMYK *.tiff if I use US Web SWOP v2.
The only way I've achieved an unacceptable 99.9% difference between the original RGB and the CMYK tiff is when I use the direct export provided by GIMP 3.0 (without a plug-in). When I open the file in other programs, the tonal differences are quite large. But CURIOUS!: When I open the converted image in GIMP, whether or not you enable soft-proof, it looks great. As if GIMP had done its job well, but the other programs don't recognize it. I don't know why this happens.
Although Fogra emphasizes offset, I prefer Fogra39 over US Web SWOP v2 because it offers far fewer out-of-gamut colors. This can be confirmed within GIMP or Scribus. It also depends on your needs.
Within open source software, another great option for creating a PDF for printing is to use Scribus to generate a full CMYK:
- Export as PDF/X1-a (if there are no gradients and/or transparencies).
- Export as PDF 1.4, 1.5, or 1.6, enabling Color Management, choosing Printer (Color tab), and if bleed marks or crop marks are not needed.
- If you are going to export as PDF/X-4, it forces you to convert RGB images to CMYK beforehand (with Cyan stand-alone, for example)