Black ink fill rate control in CMYK?

[mykee]

The printer returned the cover saying that the black colour strength is too high, the maximum CMYK fill rate is 280%. I am using FOGRA39L_VIGC_300 profile, but this is too much. I am currently using Soft Proof Adjustment with ICC 260, but in some places this goes up to 280%.
Where and how can I control the black fill ratio in Publisher (like in Acrobat) so that the printer doesn't send my cover back? How can I check which is the darkest point in an image?

In the meantime, I found this option in Preflight (it wasn't in version 1.x), so I'll see how much and how it helps.

 

It seems this is really useful Prefligfht tool. Then the question is: if I use the FOGRA39L_VIGC_300 profile, why does the value go above 300% and Preflight does not report an error?

[Dazmondo77]

I've had this problem when artwork goes for 12" vinyl LP release, and for some reason on all LP artwork I've done upto yet, the print service providers state they need the maximum ink density to be below 260% ??? and that is using three different production plants (2 uk 1 Germany) I never found out why only 260% but anyway, my way of dealing with this is to use blend ranges and find the darkest black on your artwork in Pub Photo persona by using the info panel and placing the sample location targets in roughly the darkest area then I'd usually make the artwork container background a bright green so you can see how blend range adjustment effects your background, then when you're happy, change the green to a rich black (I usually go for a C20 M20 Y20 K100) and tweak to your liking while keeping an eye on the info panel sample markers you can also Shift CMD V copy the blend range adjustment throughout any other flagged artwork --- not sure I've explained very clearly so I've done a screen grab        

[lacerto]

Obsolete.

[thomaso]

1 hour ago, lacerto said:

Note how Affinity apps appear to require refreshing of placed RGB images before ink limit of a changed profile takes effect (something that does not happen when using e.g. InDesign, so there both early and export-time profile reassignments are correctly applied for RGB objects when exporting to PDF) -- I have a feeling that this did not happen earlier within Affinity apps, either. It also seems that the macOS versions are even more broken as there (at least with native chip on macOS Sonoma 14.2.1 and latest Publisher 2.4.2) assigning a different CMYK profile does not seem to have effect on conversion of neither native art in RGB color mode (the RGB 0, 0, 0 black rectangle), nor in RGB image, so on macOS profile-based TAC limiting is badly broken.

What a nasty issue. It also occurs to me in APub V1. After assigning the other document profile then switching the colour model in the Colours Panel does not refresh the image and TAC values (but applies a fill colour, even if the wells are set to none before). Instead I can either replace the image (which is not useful) or save + close + reopen the document to get the profile with correct colour values / TAC displayed. Without this additional workaround also an export shows the values of the former document profile (when placing the image) though PDF/X-1 is using the correct intent for export.

[lacerto]

Obsolete.

[thomaso]

11 hours ago, lacerto said:

good workaround

… whereas the issue appears more problematic than usual issues because this doesn't get obvious neither in .afpub nor in an exported PDF. (… unless the user checks the TAC as you did in your video, which should not be necessary after assigning a profile to the document or for PDF export, especially for PDF/X).

Do you know if this was ever (bug-)reported for V2 ? (… I never have noticed an according bug report for V1 and I have V1 only).

[mykee]

@lacerto your video is very useful, and this is exactly the little tool I miss in Affinity (Total Area Coverage), which I could really use to easily check if I am exporting good color coverage or not.  Here I use FOGRA39 for my prints, so by default I use the FOGRA39L_VIGC_300 profile and put the RGB images on that, but for some reason it still crosses the 300% limit and exports 325%. If I put a Soft Proof layer with ISO ECI 300 on it, it has already taken back the tints, which may be a temporary solution, but it can distort the colours a bit.

[lacerto]

Obsolete.

[lacerto]

Obsolete.

[lacerto]

Obsolete.

 

[NotMyFault]

6 hours ago, mykee said:

@lacerto your video is very useful, and this is exactly the little tool I miss in Affinity (Total Area Coverage), which I could really use to easily check if I am exporting good color coverage or not.  Here I use FOGRA39 for my prints, so by default I use the FOGRA39L_VIGC_300 profile and put the RGB images on that, but for some reason it still crosses the 300% limit and exports 325%. If I put a Soft Proof layer with ISO ECI 300 on it, it has already taken back the tints, which may be a temporary solution, but it can distort the colours a bit.

You may try this. A simple channel mixer adjustment can do the trick to show areas exceeding given limits.

 

[lacerto]

Obsolete.

[mykee]

@lacerto Yes, this could be a problem, because the shadows of the texts exceeded 260-300%, so it was not only the conversion of the images that was the problem, but also the text effects. So for PDF export these shadows were not converted according to ICC.

 

@NotMyFault Thanks for the article, I will definitely look into it!

 

Update1: I uploaded the video where I show the shadow. What's interesting is that even at ICC 300, the Total ink ratio goes beyond 300, and even with Soft Proof, it only goes lower when using a different profile. Here are profile datasheets:

https://www.color.org/registry/Coated_Fogra39L_VIGC_300.xalter

https://www.color.org/registry/Coated_Fogra39L_VIGC_260.xalter

 

Update2: I also made a video about what happens when I change or convert an ICC profile. The shadows don't go below 300 in either case, even with the reduced profile.

 

 

[lacerto]

Obsolete.

[mykee]

@lacerto In the case of Soft Proof, if I select an ICC of 300 that is similar to the original, it does not noticeably degrade the colours (e.g. you can see in the video that if I select Fogra39, which is not 300) it already improves the shadows. Although it's strange, because the point of Fogra39_VIGC_300 is exactly that it takes the richness back to 300 compared to the plain Fogra39, it's still the wrong one.
For shading, however, it might be interesting to switch to CMYK color and not use rich black shadows. Although the ICC profile is supposed to soften, it doesn't for multiply. Or the other is that for a CMYK project, the program should offer CMYK black by default for effect shading, not RGB. Or convert them to ICC profile when exporting.
Here's the video where it turns out that you should work in CMYK for shadows too, not use the default RGB as a routine.

 

 I must admit, until now I thought that if I worked in ICC 300 profile, whatever colour I specify, Affinity would convert it to the correct colors. Apparently it doesn't.

[lacerto]

Obsolete.