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PDF CMYK. Different programs show different values. How do I know where the correct one is?


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PDF Studio Pro shows the following value.

2024-08-12111310.png.ca172106a08c9c29bab03172d45280c9.png
Adobe Acrobat shows that everything is OK (i.e., a blank page) with the same settings.
How do I know which is correct and if it is correct? File was exported from Publisher.

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If I understand right you expect the image to be grayscale? If you open the PDF in Affinity (with this colour profile) it would have the button "K Only" automatically activated if it's grayscale image.

macOS 10.14.6 | MacBookPro Retina 15" | Eizo 27" | Affinity V1

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2 minutes ago, thomaso said:

If I understand right you expect the image to be grayscale? If you open the PDF in Affinity (with this colour profile) it would have the button "K Only" automatically activated if it's grayscale image.

I expect nothing to be on the page, as shown by Acrobat, because this image is gray.

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Vor 5 Minuten sagte Anto:

I expect nothing to be on the page, as shown by Acrobat, because this image is gray.

Yes, my described workaround via Affinity doesn't offer a colour separation view option (without displaying black like your PDF viewers can do) but it does auto-activate "K Only" for grayscale images.

macOS 10.14.6 | MacBookPro Retina 15" | Eizo 27" | Affinity V1

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6 minutes ago, lacerto said:

I have both apps. Could you post one sample page so that we could compare the output. Basically if you had in Publisher the CMYK target profile set as WAN-IFRAnewspaper26v5 and exported to "Document color profile", you should have the colors output as expected. In Adobe Acrobat Pro, you can use the Object Inspector view of the Output Preview window to examine true native values of the job and see actual image color spaces and percentages that each selected object has on RGB and/or CMYK channels, or if it is 1-channel (e.g. DeviceGray, or if it has everything in K-channel).

Here are files. Picture from pixabay was converted in Photo Persona to  WAN-IFRAnewspaper26v5_gr

1723454886.jpg

CMYK.afpub CMYK.pdf

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Just now, lacerto said:

The resulting PDF is DeviceGray, so you should be good.

But why do the two programs have different results? If I only have PDF Studio Pro, how do I know that the output in CMYK is correct?

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1 minute ago, lacerto said:

Note that you had in your post the CMYK simulation profile selected in PDF Studio, rather than the grayscale version (ending with _gr). If you select the correct target profile, it shows the Black plate only:

output_preview_pdfstudio.jpg.9875e03a0662fddbed8e85cfaa006450.jpg

Nevertheless, I think that it should show Device Gray values in K channel only also when using CMYK simulation profiles. It would be different if the file were ICC dependent but as it does not request translation, gray values should not be converted to multi-channel. 

It's just strange to me, because in Acrobat I also select CMYK, and everything is displayed correctly.  That's why I have this question. I also have color pages.

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48 minutes ago, anto said:

If I only have PDF Studio Pro,

... and Affinity. The used document/export profile appears to be grayscale only and thus no CMY would be in the PDF.

If Affinity opens this PDF it estimates & auto-assigns a grayscale profile (even though the PDF has no output indent included) which is currently set in the app preferences (… and thus the mentioned "K Only" button is neither required nor available for this image).

Bildschirmfoto2024-08-12um11_35_14.jpg.96919c04aff748d964f63046e7be1acc.jpg

42 minutes ago, lacerto said:

When you have DeviceGray, the output simulation profile should not mess up the color channels even if you use CMYK simulation profiles (rather than grayscale profiles), the device gray should only show in K channel, as it does in Adobe Acrobat Pro.

To me if I have a CMYK profile selected as simulation profile the separation view does not show a K channel only but CMY channels, too, while these are empty for this grayscale PDF. On the other hand, if the simulation profile is set to a grayscale profile, only the K channel is displayed without CMY channels that can be enabled/disabled – even for a PDF that contains CMY.

Bildschirmfoto2024-08-12um12_04_43.jpg.0bc4385c5f4aed570b56ff1eea96596a.jpg

Bildschirmfoto2024-08-12um12_01_38.thumb.jpg.c34c7587211e36407d92bab9de200263.jpg

macOS 10.14.6 | MacBookPro Retina 15" | Eizo 27" | Affinity V1

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