Color inconsistency of published PDFs on MAC - Critical bug in AC28/27/..

[Pavel_N]

For JPG images that are inserted into Layout as an external drawing, significant color changes occur after publishing to PDF via Publisher.

In Archicad Layouts, JPGs appear the same compared to the source file, but the PDF export from Publisher is significantly color-shifted (both in terms of color tone and image brightness). The output is completely unsatisfactory, a PDF with embedded images cannot be presented or printed seriously in this state.

I did a small test to demonstrate the problem. In Layout, I created colored rectangles as fills, made a printscreen of them and inserted a printscreen next to the original. I attach the test result in the attachment.

On Windows everything is all right, Its only MAC Silicon issue. The issue also occurs in AC27 MAC and maybe in older versions?

[Lingwisyer]

My first thought was that it had to do something with the bitdepth that the images are being published at, but your first three colours being straight RGB should not be affected at any logical bitdepth... I assume you have dug around in the PDF publish options?

[Karl Ottenstein]

I don't have an answer, but can suggest where to look...to understand it but not to solve the issue:

JPEG images use the sRGB color space.  When viewing on-screen, you are seeing the current Mac display color profile's interpretation of those colors.  When the PDF is created, the color space for the embedded image could be changed to RGB or Adobe RGB etc....and when viewing... even if the RBG color codes are identical, the PDF viewer could be using a different color profile to interpret that color space.  For example, InDesign let's you look at colors with the monitor's color profile, or the printer profile for a particular paper.

What I could not see, and why my post is really not helpful, is any way on the Mac to select the color space or the color profile for a PDF.  Certainly using File > Print from a Layout and then the Save as PDF option has no color options.  And, using Publisher to publish to PDF... those PDF settings also don't have settings for embedded color space or embedded color profile.  It's very interesting that it works properly on Windows, but it seems it would take some detective work to figure out why this is happening on Mac... but without any settings options for creating the PDF, it would only be academic to figure out why its happening.  Unless of course it is something Graphisoft can fix.

[Karl Ottenstein]

I Googled a bit and found these PDF export settings for Affinity Publisher which do indeed let you choose the color space and profile for the exported PDF there.   I wonder if that's something we should be adding to the Archicad wishlist...other than you said everything works fine on Windows without these extra settings...

 

[Lingwisyer]

Ah, you are thinking that maybe the actual colour space of the jpg is being changed to be different from that of the rest of the PDF? Sounds like a possibility.

[Pavel_N]

Can I ask you to test and replicate the problem on your Mac computers? Just insert any JPG image into Layout and export it to PDF via Publisher and compare them? Do you see a similar color shift as I do?

If I use print to PDF directly from Layout (native Mac PDF printer) instead of publishing, the colors are correct. So it's a problem within the ArchiCAD export.

[Pavel_N]

The reasoning is probably correct. But I'm not sure that the differences in color would be so huge in the case of swapping commonly used color spaces. I guess the problem lies in the incorrect interpretation/deformation of a specific color space by ArchiCAD.

[vlahtinen]

Yes, we're having the same issue and also using Macs.

[Karl Ottenstein]

Yes, I'll try later today (just morning here now) ...unless someone else confirms sooner... but am glad you posted that File > Print > Save as PDF did give the correct colors as that was what I was going to suggest as a troubleshooting step for Publisher's PDF.  Thanks for that.

[Karl Ottenstein]

I agree that sRGB to RGB or Adobe RGB should not cause this issue.  But, let's say that the Archicad PDF publisher converted to CMYK (probably a more likely color space for eventual printing)... then sRGB to CMYK and back to sRGB could indeed give different results if the conversion protocols were not symmetrical.  Of course, none of C, M, or Y can be represented exactly in RGB either, but I'll try adding those colors along with the RGB primaries when I test your workflow  after I wake up some more...