Color Profile Export Issues

[thoy]

Hello,

I am having a persisting issue when trying to export a PDF using Affinity Publisher. I am trying to export a particular color profile for print. What continues to happen during export, is the blacks in the Tiff files are being rewritten. The blacks are set to a 30%/30%/30%/100% build. Every PDF export rewrites them to something like 70%/80%/60%/90% - which is giving me a print problem because the black K is not staying at 100%.

 

I have tried changing the Color Profile settings in the Global Publisher settings, the Document settings, and in the PDF export preferences. But the export continues to be wrong when I check it. I would greatly appreciate any help you can give on this!

[lacerto]

Color management within Affinity apps can be quite tricky and results are dependent on what kinds of images (possibly with embedded profiles), in what kind of a document (RGB or CMYK, which document color profiles are involved), which color profiles have been defined in the app settings (this would be important especially if importing PSD, Photo or other files treated as documents within Affinity apps, or if you have e.g. RGB document and you have an implicit CMYK document profile) and how you export it, and which viewer you are using to examine the results, so an example or more information would be needed.

As a general advise, you are going to get most likely what you expect if your document CMYK color mode matches the target CMYK color space, and you either place TIFF files without an embedded color profile, or TIFF files with an embedded profile that matches your document CMYK color profile, and you then export to PDF by using the document color profile (and do not change the profile at export time). Then, depending on the viewer, you might also need to make sure that the viewer simulates the correct target profile and does not perform recalculations of actual color values saved in the viewed file.

PS. Welcome to the forums!

[stokerg]

Hi @thoyand Welcome to the Forums,

If you could provide a sample afpub file and make sure the TIFF file is embedded, that would be great.  If you can also let us know which PDF export settings you are using, we can offer some advice.  If you'd rather not upload your files publicly to the Forums, then please use the private Dropbox link here.

[thoy]

Hi @stokerg thanks for getting back to me. I just uploaded the latest version via the Dropbox link. I have tried essentially every single export option to try and achieve the correct color. I have tried going into Publisher settings and changing the global CMYK profile. I have tried going into the Document settings and changing the profile there. And I have tried changing the profile in export options.

 

This is a print project and I'm working with a designer who did previous color correction in the TIFF files. He has also tried many export options on his end.

 

We are trying to achieve this color profile: 280% 30% GCR Medium / SWOP (Coated) 30%, GCR, Medium. From my designer: "The easiest thing to point out is that the blacks in the Tiff files are being rewritten. The blacks are set to a 30%/30%/30%/100% build in the Tiff files. Every pdf export I've tried with Affinity rewrites the blacks to something like 70%/80%/60%/90%.....the biggest printing problem being that K doesn't stay at 100%."

[lacerto]

Hello @thoy,

My first question is: which version of Publisher are you using?

I have been reviewing Affinity color management related issues for a few years, and do not expect rapid changes, but it seems (and I hope I have not just made some stupid mistake) that the recent 2.x versions finally show some development and improvement -- at least in perspective of users with some experience of using other professional page layout apps. Namely: it seems that Affinity apps (at least Publisher) now, similarly as e.g. InDesign, discard embedded CMYK profiles from TIFF and JPG files, meaning that placing a raster image with an embedded CMYK profile that conflicts with document CMYK color profile, or with the CMYK profile selected at export time no longer results in conversion of CMYK values of these images. I am not sure if this is optional (e.g. is or will become a color profile policy setting, but possibly -- and hopefully -- so, since needs are different in the three apps of the suite).

Native CMYK color values (of shapes and text) will, as they basically should be (without an option available that would explicitly prevent this), as will be color values of .aphoto and .PSD files with a conflicting embedded CMYK profile, probably because of their potential complexity, as they can hold vectors/text/etc., be complex jobs.

Anyway, to keep things simple when placing CMYK images, it is advisable, if at all possible, to use TIFF or JPG images with no color profiles embedded, in which case they will be assigned with the document CMYK profile and their native colors will be passed through, also when changing the CMYK profile at export time (something that normally should not be done if CMYK definitions are used in text and other native objects). As mentioned, you can now (at least in recent 2.x versions) also place CMYK TIFF and JPG images with embedded and conflicting profiles because they will be ignored and native colors of images will be passed through. Note though that in version 1 apps JPG and TIFF CMYK images with conflicting profiles will have their native colors recalculated.

Along with this change many issues with K100 definitions becoming inadvertently converted to four-color blacks at PDF export will be avoided.

The attached PDFs demonstrate how K100 definitions are translated and retained in different situations. The first PDF is exported using the document color profile, the second is exported to a different CMYK profile.

 webcoated_dg30.pdf

isouncoated_yellowish.pdf

Note that the Publisher document in these examples uses pretty much the kind of a CMYK profile you mentioned, based on SWOP Coated with max 280% TAC and 30% dot gain, as will some of the placed K100 images. As can be seen, the only problematic images are .aphoto files, which are recalculated when there is a profile conflict. RGB black and K100 and 400% black in native shapes and text, when there is conflict, will also be converted, as expected. 

The second big question is: which app are you using to verify the color values of exported PDFs? The 30% 30% 30% 100% build especially sounds dubious, not something that would appear as a result of an ICC profile based conversion of CMYK values (but rather a CMYK representation of an RGB/Grayscale black). Anyway, it is good to notice that Affinity apps by default embed the document ICC profile when exporting to press-related PDFs, which is in many ways problematic, because it often makes an all CMYK (already fully resolved) file ICC-dependent, and when such a file is viewed in e.g. Adobe Acrobat Pro, the displayed color values in Output preview depend on the selected simulation profile, and the correct profile will not be automatically selected (unless in PDF/X based exports). This means that inherent values are recalculated ad-hoc on display if the correct document color profile is not activated (in Output Preview). Most PDF viewers do not support selection of a simulation profile and do not suffer from this issue, but this confusing default export method (which in other page layout apps can be done, too, in case the default and recommended settings are deliberately rejected and changed) continues to trouble both users of Affinity apps and production personnel, and may actually result in inadvertently converted (or unnecessarily changed) print jobs. 

There are also other related issues -- though not relevant in your situation -- in Affinity produced PDF exports (e.g. so called PDF "version incompatibility rules" dealing basically with transparency flattening), which may cause inadvertent rasterization, which in context of K100 objects results in translation of mere black to four-color blacks.

These kinds of problems cause much insecurity, and in lack of proper preflight / prepress tool, it might be a good idea to open exported PDFs in Publisher (or another Affinity app) and examine the color values. In most situations (but not always) an opened PDF file shows colors accurately and at least helps making correct production decisions.  

[stokerg]

Hi @thoy,

You've had some great advice from @lacerto.

Could you also upload the colour profile you've used?  I've tried to do a colour check on the PDF but as I don't have the colour profile, I don't get the correct results, which is to be expected without the profile installed.

From the checks I've been able to do, I can see the image in the PDF has had the 'SWAP (coated), 30%, GCR Medium' applied, so this could very well just be an issue with how the PDF being is checked for errors.

[thoy]

Hello @lacerto thanks for all this info! Very helpful. I'm using Publisher 2.3.1 - to give more background on the issue, the PDF is for a CD printing project and I already received print proofs that had incorrect colors while printed. The CMYK values are resulting from a conversion from RGB, where there very rich dark browns. My designer is using Acrobat (I believe) to verify color values.

 

Would you say that a good course of action moving forward would be to try using TIFF files that have no color profile embedded? The main reason I have ended up in this situation is because I'm trying to fix a print color issue that already occurred (though this issue was with the colors, not the ink levels). The reason the TIFFs have embedded profiles is to fix the washed out colors that I received with my first print proof.

 

@stokerg I just sent the color profile for you to take a look at. Is it possible that using Adobe programs to check the PDF for errors is actually producing the errors? And if so, what program do you suggest I do color checks with? Is it possible to do this with Affinity Publisher?

[stokerg]

Hi @thoy,

Thanks for the profile.  With that installed, if i check your PDF in Acrobat and also remember to set the Simulation Profile, i get 100K for black in the TIFF file.

I get the same values you mentioned in your first post if I don't set the Simulation Profile to match that of the PDF.

[thoy]

Hi @stokerg thanks for checking. So if I'm understanding correctly, the colors are actually correct, it's just crucial to make sure that the Simulation Profile is set to be the right one. Is this correct?

[stokerg]

1 minute ago, thoy said:

So if I'm understanding correctly, the colors are actually correct, it's just crucial to make sure that the Simulation Profile is set to be the right one. Is this correct?

You need to set the simulation profile, otherwise you will get the wrong values.  I'd encourage you to get this confirmed that the colours are correct and as always with anything to do with print, getting a proof copy first so you double check things, is always a good idea!

[lacerto]

5 hours ago, stokerg said:

From the checks I've been able to do, I can see the image in the PDF has had the 'SWAP (coated), 30%, GCR Medium' applied, so this could very well just be an issue with how the PDF being is checked for errors.

The ICC profile would be important if it is embedded in the PDF (as it is when using the default press ready CMYK PDF export preset of Affinity apps), and when using a viewer like Adobe Acrobat Pro, which in the Output Preview dialog allows the user to pick an ICC profile to simulate when interpreting the shown (calculated) color values.

However when using a custom color profile, like the one I used in my demo, which is based on US Web Coated SWOP v2 but just has Dot Gain value increased to 30% using Photoshop, and the profile then extracted from a TIFF file where it was embedded using EXIF tool, the resulting ICC profile is not one that Adobe Acrobat Pro lists (I thought that it lists all that are placed in the system color profile folder, but obviously it does not). That means that I cannot select the correct simulation profile to match with the ICC profile embedded in the file, and would accordingly see misleading color values in the Output Preview window, as demonstrated in the video below:

 The video also shows (in the PDF viewed on top right) how selection of simulation profile is irrelevant (does not have any effect) on a job that it "DeviceCMYK" (not ICC-dependent), and how PDF/X-based job has an obligatory output intent indicating the target CMYK profile of the job, and automatically selected as the simulation profile. Here the actual ICC profile used in the job can be used by Acrobat even if it cannot list it in jobs where the color intent is not included.

The files used in the video also demonstrate how grayscale 0 and RGB 0, 0, 0 black (virtually identical color definitions) will result in the kinds of even builds of CMY values, and 100K when converted to a CMYK-based PDF, so one possible explanation to what OP might have experienced is having originally defined black as a grayscale value, and expecting it to be handled as K100 values, similarly as e.g. in InDesign, while in Affinity apps gray values in a CMYK color document are treated as RGB values that always result in four-color blacks. [UPDATE: Note though that grayscale images that are placed in a CMYK document have the "K-Only" option automatically applied on them, forcing the gray values being handled as K-only values; so if the unexpected color values are only related to TIFF and other placed black images, this does not explain what happened; so it might have been "view-only" kind of issue.] 

 blacks_pressready_icc_embedded.pdf

blacks_pressready_icc_not_embedded.pdf

blacks_pdfx1a.pdf

Here is the ICC profile that I created, perhaps somebody can have Adobe Acrobat Pro show it in its list of simulation profiles

USWebCoatedSWOPd30.zip

[lacerto]

I noticed that the ICC profile extracted by Exiftool was corrupted (none of the Adobe apps could recognize it as a valid ICC profile, even if Affinity apps did) -- it seems that Exiftool has problems extracting correctly profiles from ZIP packed TIFFs, so I embedded it in a JPG file, and re-extracted, and this time the resulting ICC profile was accepted by Adobe apps, as well.

So here is a demonstration on applying the correct, matching simulation profile on an Affinity created default press PDF which has a document CMYK profile embedded in the created file:

 

 

And here is the corrected ICC profile packed in a zip file:

USWebCoatedSWOPd30.zip