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You have to strip the profile from the original, save over it, relink, replace the profile, save over the image again and then relink again to get InDesign to acknowledge the profile.
There’s no need to resave the files, you can select an image and use Object>Image Color Settings to reassign or assign any CMYK profile to the image
But, there can’t be two different ouput destinations, so in a case where you are converting to an alternate CMYK profile in Photoshop in order to produce a quadtone with a heavier black plate, it is important not to include a profile otherwise there will be a CMYK-to-CMYK conversion when the placed quadtone’s embedded profile conflicts with the ID document’s profile.
So here I’ve converted to a profile with an extra heavy black plate and the middle gray at the bottom converts to 30 | 21 | 22 | 38:
If I place the image in an InDesign doc with an extra light black generation profile as the CMYK assignment, the output values for my placed quadtone are unchanged, but only if the image profile is Document CMYK:
If the embedded profile is honored, there will be a CMYK-to-CMYK conversion on an export to PDF/X with Document CMYK as the destination. The image will be converted to the document’s CMYK profile and the heavy black generation will be lost—the output values will be converted to 53 | 44 | 42 | 7:
The InDesign Preserve Numbers (Ignore Linked Profiles) CMYK Policy is designed for cases like this.
The images *have* an embedded profile. I don't want to assign another profile. And the profile may not be one that I have loaded in the system.
If an image has an embedded profile and it is placing as Document CMYK, then the document’s CMYK Policy was set to either Off or Preserve Numbers (Ignore Embedded Profiles). The Policy (which is saved with the document on creation), must be set to Preserve Embedded Profiles in order for the embedded profile to show in the Links panel. If you want to change a document’s policy, close it, set the CMYK Policy to Preserve Embedded, check Ask When Opening in Color Settings, reopen the document, and you will get a dialog allowing you to change the policy and update the placed files—there is no need to edit the images.
PDF/X-4 will maintain the ICC profile information on individual CMYK images, but the problem is InDesign has already converted the images
PDF/X-4 only tags CMYK objects with embedded profiles that conflict with the document’s assigned profile, all other CMYK objects export as DeviceCMYK—no profile. If I export my example to the default PDF/X-4, and set Acrobat’s Output Preview’s simulation to the Output Intent, the same output numbers problem occurs when there is a conflict. The opposite of what you seem to expect happens, the image is converted into the Output Intent profile and the custom heavy black separation is lost:
The bottom image listed as DeviceCMYK has the correct heavy black separation
PDF/X-4 will maintain the ICC profile information on individual CMYK images, but the problem is InDesign has already converted the images 😞
While you can convert placed images on export by setting a Destination, InDesign does not convert placed images in the document, it only allows you to change the profile assignments, you can’t actually convert an image. Separation Preview is a simulation, and shows the expected separation output numbers for an export to Document CMYK, or a Proof Setup if Proof Colors is on.
The default PDF/X-4 preset with No Color Conversion tags some, but not all color—it only tags color that does not match the document’s assigned CMYK profile. So if I place a CMYK image with a profile that matches the ID document profile, that image will export to PDF/X-4 as DeviceCMYK (no profile):
The top image’s embedded profile matches the document’s assigned profile and will export as Device CMYK:
The bottom image’s profile conflicts and will export with it’s profile:
The PDF/X-4 inspected in Acrobat
I want to be sent PDFs from InDesign that haven't been automatically converted and where each image has its embedded profile intact so that I can know (or try and work out) its history.
You can do that now. Set the document’s CM Policies to Preserve Embedded Profiles, then on export set the Standard to None, and set Output to No Color Conversion, Include All Profiles. In this case all images and native InDesign objects will include profiles
How do you check the separations in the PDF?
The actual CMYK values of native fills show in Object Inspector, here’s a fill with default [Black] 0|0|0|100:
The Separation preview accurately shows a conversion into the Simulation Profile—the expected output space. If the output destination conflicts with the CMYK profile the output CMYK values are going to change (DeviceCMYK values would simulate as unchanged).
So my ICCBasedCoated GRACol 100% black fill output to a US Sheetfed Coated destination is going to convert to 84 | 73 | 74 | 65, there’s no way around that.
If I set the Simulation profile to match an image or fill’s embedded profile, then the Separations show the object’s actual CMYK values:
Look at the result -- the CMYK values are altered so that the image will print correctly on a different press, but the K channel is retained.
And it screws up the gray balance. When the color is in gamut I expect conversions to maintain the color appearance. The point of the heavy black plate separation is to make it easier to control gray balance on press—this device link conversion adds a blue cast into the separation numbers.
Device link conversions make sense when you are up against total ink problems or single color blacks and grays, but for subtle gray balance where neutrality is the goal it doesn’t seem so great:
Converting from RGB to PSO Coated v3 or PSO Uncoated v3 using the conventional ICC profiles in Photoshop will also give you neutrals that are blue biased.
I’m not seeing that, a conversion directly from AdobeRGB to PSO Coated produces an exact appearance match with no blue cast—the return RGB values are perfectly neutral for the direct conversion, but are not for the device link conversion.
Bottom left is the direct conversion, bottom right is the RGB>CMYK>DeviceLink conversion
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