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hschneider

White appears yellowish when importing RGB bitmaps

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White RGB bitmaps appear yellowish, when they are imported into a CMYK document.

Scenario:
Affinity Designer 1.7.1 on macOS 10.14
Document is CMYK/8 with color profile Euroscale Coated V2
Bitmap is a RGB JPG with profile Adobe RGB

How to reproduce:
Drag and drop barcode.jpg into the test doc. See files attached.
The JPG is pure white when opening it in the Apple Preview app or Affinity Photo.


-- Harald

Bildschirmfoto_2019-07-19_um_17_18_46.jpg

barcode.jpg

test.afdesign

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Hi hschneider,

As far as I can tell the issue appears possibly to be with the default CMYK and RGB values of the non transparent background when creating a new AD file. For me if I create a new AD document and set the Colour Format to CMYK, firstly I have an issue in that Euroscale Coated v2 is missing from the dropdown as an available colour format, yet it is available in both AP and APub! I've reported this as a possible bug here...

18 hours ago, Hangman said:

When creating a new CMYK/8 AD file, Euroscale Coated v2 is missing from the colour format dropdown menu as an available colour format but is available in both AP and APub. However if I create a new CMYK/8 document in either AP or APub and click Edit in Designer, Euroscale Coated v2 is now available as a colour format option in AD if I go to Document Settings/Colour Format.

635619380_CMYKColourProfiles.thumb.jpg.5c276de641343a512e77318156f99e01.jpg

Euroscale Coated v2 is an option for newly created AP and APub documents and strangely if I open a CMYK AP file created using Euroscale Coated v2 as the colour format and then select Edit in Designer and go to Document Settings, Euroscale Coated v2 now appears in the dropdown list as an available colour format.

In AD the default non transparent 'white' background has a value of CMYK (0, 1, 4, 0) slightly yellow.

For me the default colour slider settings in AD for a CMYK/8 U.S. Web Coated (SWOP) v2 document (I can't select Euroscale Coated v2 as it is missing from the list, however opening your test.afdesign file the CMYK values are the same for Euroscale Coated v2) are CMYK (0, 0, 0, 10) which translates to RGB (231, 232, 233) on a new document when the colour palette is switched but on your test.afdesign file the CMYK (0, 0, 0, 10) translates to RGB (220, 222, 229), so not even consistent.

If I create a new AD document in RGB/8 with the Adobe RGB colour profile, the default colour slider settings are RGB (235, 235, 235) which translates to CMYK (5, 5, 5, 0) when switching colour palettes.

So long story short(ish), I think the reason the white of your barcode apppears 'yellowish' when placed in your AD document is because the default 'white' you are seeing in your file isn't true white, but an off white.

Having said that, if you export your barcode as a CMYK Jpeg file and then drag it onto your test.afdesign file it appears correctly with matching whites, so this could simply be an RGB/CMYK conversion issue you are seeing, i.e. importing an RGB file into a CMYK document.
 

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Thanks for the detailed description. 

When I open the JPG in Affinity Photo then is shows clear white with RGB #ffffff.
When I export it as a CMYK TIFF, then the problem appears again. The exported file has CMYK 0 1 4 0.

Meanwhile, this becomes a huge problem, because we have to remove the white background of images, which were useable in AD 1.6 without any problems.

There is definitely something wrong with the color translation between RGB and CMYK since version 1.7

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If I open the bar code in AP, with the colour format for the document set to RGB and then export both an RGB jpeg and an RGB tiff file and then convert the AP document to CMYK and repeat, exporting the barcode as both a CMYK jpeg and a CMYK tiff file, then I open two AD documents, one set to RGB/8 the second set to CMYK/8, when I import the RGB jpeg and RGB tiff files into the RGB AD file, the whites match exactly and the same is true when dragging the CMYK jpeg and CMYK tiff barcodes into the CMYK AD document.

The issue though is that the test.afdesign file doesn't have a 'white' background, as you say if you sample it, it has the values CMYK 0, 1, 4, 0 so it is logical that the barcode 'white' isn't going to match the 'white of your test.afdesign file if that makes sense.

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@mac_heibu: The original file is attached to my 1st message.

It IS a color conversion or profile issue:

I have loaded the original RGB jpg into the Apple ColorSync Tool and assigned the EuroScale Coated V2 profile.
After this, the output is a CMYK jpg wich shows in perfect white in AD.

So the problem seems to be color profile handling or conversion in AD.

 

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The issue though is that the test.afdesign file doesn't have a 'white' background, as you say if you sample it, it has the values CMYK 0, 1, 4, 0 

IMHO this is the result of assigning EuroScale Coated V2 as a doc profile.There all the trouble begins.

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I'm not sure, I've just created a new CMYK AD doc with using EuroScale Coated V2 and when I sample the default background I have CMYK 0, 0, 0, 0 which means that dragging the two CMYK barcodes (jpeg and tiff) to the file results in a matching white background.

Can you do a quick test and create a new CMYK AD file using EuroScale Coated V2 and sample the default white to see what CMYK values you have?

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I assume, your document has a problem.

What I did:

  • Created a new document with thre same document profile (Euroscale Coated v2).
  • Placed your barcode in 3 variants (• yours without color profile, what should never be done, • with sRGB profile, • with Euroscale Coated v2 profile)
  • Result: All is ok.

Annotation: The bar code shouldn’t be produced the way you do! Because a RGB image’s black will be converted in multicolour black during CMYK output. And especially for bar codes (and small text) this should be definitively avoided because of possible registration inaccuracy.

Please have a look at the attached files.

Sample.zip

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Thanks for testing. Now things get more weird:

Your sample doc works perfect. All files I drag onto your doc are rendered perfectly.

Now I create a new doc, with the same settings: Profile Euroscale Coated VS, CMYK/8 and I run into the same issue again.

BTW:
The barcode has been created by a customer of mine. He has the same issue on his machine.

So there must be something else different on your machine and ours here.

Just a guess:
Do you have an external monitor attached to your Mac?
If so, is it an Apple or 3rd party product?
Which macOS do you run ?

There are color profile issues mentioned in the forum, which are related to external monitors.

 

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No second monitor. I am running Mojave, latest version. But I am sure that this is not the issue.

Perhaps it is worth while, to have a close look at your monitor profile. (Hope, it isn‘t sRGB or something like this.)

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To clarify from my perspective, I'm running a MacBook Pro with no external monitors attached. My screen colour profile is set to sRGB IEC61966-2.1 and likewise Mojave latest version but I also don't think that is the issue.

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I'm currenly in agreement that it appears initially to be an issue with the test.afdesign document. Is it possible you could create a new AD document using the same colour format as the test file and post it here?

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My monitor profile is the standard one, which comes with the iMac.

The test doc IS created with the same settings as the working sample.

Can we compare the color settings in AD, please ?
See screenshot attached.

 

Bildschirmfoto 2019-07-24 um 18.38.09.jpg

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Hi mac_heibu,

I'm not sure I follow, surely you have to establish a particular screen colour profile for you monitor whether that be sRGB, Adobe RGB or whatever? Your monitor must be set to a particular colour profile as well? Either way, I don't think this is the issue and we're perhaps going down a 'red herring' path as it should make no difference in terms of the monitor colour profile with respect to the files in question.

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Looks like something AD writes to the file, when it is created:

The sample created by mac_heibu works fine at my machine.
My test file with the same settings shows on Hangman's machine a background with CMYK 0 1 4 0 and does not work on my machine.

 

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I was actually referring to the colour profile of my mac screen rather than the colour profile set within AD, but matching your Adobe RGB colour settings I still don't have an issue.

screen-colour-profile.thumb.jpg.1543c2faf8e8d27473398fa4f3191316.jpg

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This seems to be where the difference lies. If I create a new AD Euroscale Coated v2, CMYK/8 document, the CMYK values for 'white' are CMYK 0, 0, 0, 0... really unsure why your version is giving a different result, i.e. CMYK 0, 1, 4, 0 but can only assume this is the cause of your barcodes appearing as though they have a yellowish background.

myTest.thumb.jpg.d6ce2565af1daca5a65038af46672ef0.jpg

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Looks like this is only a part of the problem:

When I assign the profile Coated Fogra 27, the background samples to CMYK 0 0 0 0, but the test jpg is still yellowish.

 

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When changing the doc profile to Coated Fogra39, the RGB bitmap is imported correctly.

On my machine, the doc background and the bitmaps's white both sample to CMYK 0 0 2 0.
Both appear bright white, as they should.

I still believe it is some profile and / or multiple monitor related bug.

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