Converting to Destination in ID

[Gregg]

I'm having a hard time wrapping my head around what might be a very simple answer.

I'm working with a publisher who provided the following settings (see ColorSettings.png and ExportSettings.png). In both cases, numbers are preserved, so what are the benefits to converting to a Destination Profile? The same results would be achieved if you selected No Color Conversion, correct?

The only reason I can think of is to take care of any RGB images that may be present, which in my case there aren't. Any other reasons?

Thanks in advance.

 

[DCurry]

The RGB conversion is the only benefit I can see.

 

[kennycu]

If CMYK images were color managed within InDesign, they wouldn't get converted to your output color space.

 

[Stephen Marsh]

The RGB conversion is the only benefit I can see.

Which is not much of a benefit if the layout contains *vector* 0r0g0b objects such as black text or rules/strokes, I only see this as a benefit for raster RGB content.

Much better to use the colour conversion tools in Acrobat Pro or third party PDF Workflow software such as Kodak Prinergy, where one has control of creating 0cmy100K blacks for text and vectors instead of rich blacks.

So my advice (for those that know what they are doing) is to output from InDesign with No Colour Conversion to retain RGB content so that it can be intelligently converted based on whether it is raster, vector or text and if it is “solid” RGB black or a “tint" of RGB black.


Stephen Marsh

 

[Stephen Marsh]

If CMYK images were color managed within InDesign, they wouldn't get converted to your output color space.

To be clear, the colour managed CMYK objects would get converted if they had a different ICC profile than the output and one was using “Convert to Destination (Preserve Numbers)”.

If the colour profile of the CMYK image and the output was *EXACTLY* the same, then there would be no conversion using “Convert to Destination” or “Convert to Destination (Preserve Numbers)”.

The colour profile has to be exactly the same, if there was one object with ISO Coated v2 300% profile and the output was ISO Coated v2 profile, then the 300% total ink limit object would be converted to 330% total ink. So even though both profiles use the same characterisation/measurement data and are for the exact same condition - they are different profiles and would thus trigger a colour conversion that could be unwanted.

Despite the goal of “turn key” colour management, there is still a long way to go and a knowledgeable human can do better than a blind automated workflow that does not have any “fuzzy logic”.


Stephen Marsh

 

[Stephen Marsh]

The only reason I can think of is to take care of any RGB images that may be present, which in my case there aren't. Any other reasons?

Thanks in advance.

The publisher probably receives content in any shape or form from many different sources. Their suggested settings would be for insurance against those that don’t understand the process.

InDesign colour conversion is very basic, Acrobat Pro offers much better control over vector, raster and text in different colour modes.

It all depends on the source content. If there are only RGB raster images, then the publisher’s InDesign PDF export settings are going to be fine. If there was also RGB black vector or text content, then the result would be rich CMYK black vectors/text.

If your layout had RGB black vectors/text - then exporting the PDF with No Colour Conversion and then converting the RGB black elements in Acrobat Pro would be better as one can control the conversion to only create 0cmy100k rather than rich black.

With colour management - it all depends, there is hardly ever a “straight answer”!


Stephen Marsh

 

[Gregg]

The colour profile has to be exactly the same, if there was one object with ISO Coated v2 300% profile and the output was ISO Coated v2 profile, then the 300% total ink limit object would be converted to 330% total ink. So even though both profiles use the same characterisation/measurement data and are for the exact same condition - they are different profiles and would thus trigger a colour conversion that could be unwanted.

This is interesting. I just created a P'shop document with 2 black swatches; one had a tac of 400% the other 280%. I then placed in ID and exported using the settings mentioned in my initial post. I was happy to see, that the 400% was brought down to 330%, but surprised to see that the 280% (60/60/60/100) was brought up to 326% (89/78/62/97). I would have thought that swatch would be left alone since it was under the tac specs for that profile. Why was it changed?

I've been sending files to printers for over a decade, so I guess I should know the answer to the question above, but we've always left color as-is. We resolved TAC issues in the native files before creating the PDF. We don't rely on color management to handle anything for us.

 

[Stephen Marsh]

This is interesting. I just created a P'shop document with 2 black swatches; one had a tac of 400% the other 280%. I then placed in ID and exported using the settings mentioned in my initial post. I was happy to see, that the 400% was brought down to 330%, but surprised to see that the 280% (60/60/60/100) was brought up to 326% (89/78/62/97). I would have thought that swatch would be left alone since it was under the tac specs for that profile. Why was it changed?

I've been sending files to printers for over a decade, so I guess I should know the answer to the question above, but we've always left color as-is. We resolved TAC issues in the native files before creating the PDF. We don't rely on color management to handle anything for us.

If using preserve numbers conversion, then a conversion will take place if the image has an ICC profile that differs from the output profile.

To avoid the conversion, image profiles should be ignored.

InDesign does not check the TAC values, it just compares the profile and if the profiles differ, then a conversion takes place.


Stephen Marsh

 

[Magnus]

InDesign does what it's told to do. If you like to have a good and secure workflow you should get to know how Indesign handles color. First of all, do not turn the color management off, that won't make anything better. Instead learn how Indesign handles color and how to set up your color settings in Indesign and in your document and joboptions.

The option "Preserve Numbers" only leave object "unprocessed" that doesn't contain a profile or have the same profile as the output-profile.

You told Indesign to convert the document to Any_CMYK_profile_330.icc and thats what happened. Indesign doesnt know what TAC different object contains, it only looks at the embedded profiles and then converts the images to the wanted profile. As if you convert the same image in photoshop.

It took a few years, but now I got a grip of all colorsettings in Indesign and it's a joy to work when you are sure about whats going to happen.

 

[Gregg]

Magnus, could you elaborate on why you suggest not turning color management off.

If I am supplying final native files, or final PDFs to a repro-house who is exporting PDFs without CM, what are the benefits if I use it? We ensure all images are CMYK, and TAC is no higher than 300 before submitting files.

 

[kennycu]

"InDesign does what it's told to do." Right on Magnus!

Since I don't post much, and have recently felt this pain, I want to take a shot at this!

First, I think we all understand that converting to different printing conditions allows us to repurpose an image without changing its appearance. If you start with rgb, or whatever, and convert to 3 different presses, we would expect the image to look the same even though the CMYK values are different. Basic color management...

Suppose your document has a tagged link with an attached profile from a press that was +10 magenta. It could happen! The CMYK would pass through unchanged in your workflow. If you don't color manage that link in InDesign, that image would print green on a "normal" press. If the CMYK is set to "Preserve Profile", InDesign will convert(repurpose) that image to your new "normal" printing condition and it will look like it did on the +10mag press. Not to confuse things but if you insist on using "Preserve Numbers" InDesign gives you a second chance to color manage that image under the "Object" menu...color settings.

Try this....Using your black file you created in PS, "assign" it to another profile and save as new name. You have two images with exactly the same color values only they'll look different on screen(maybe hard to see in this example). Now place both of those images in InDesign. "Preserve Numbers...ignore" will just pass the numbers through even though you would like to honor the new profile's look. They will print exactly the same even though they looked different on screen. If your color settings are set to "Preserve Profile", InDesign will convert to the destination profile and preserve the look/difference of the new profile but use different values. The green example above would be better visually, but you can see what happens with numbers using your "blacks" file. Just view the values of your PDF in Acrobat with the output profile in the simulation menu.

Click on the objects/links in IdDesign. Go to "Image Color Settings" under the Object menu. In the Preserve Numbers workflow, the documents profile will be assumed and no conversion will take place. In the Preserve Profile workflow, the linked profile will be indicated and InDesign knows to convert that image.

There's my shot.

 

[Magnus]

Magnus, could you elaborate on why you suggest not turning color management off.

If I am supplying final native files, or final PDFs to a repro-house who is exporting PDFs without CM, what are the benefits if I use it? We ensure all images are CMYK, and TAC is no higher than 300 before submitting files.

Because if you let InDesign handles color it will save you a lot of time. You wouldn't have to manually convert all your images in Photoshop. If using the colormanagenet in InDesign it would result in a faster, better and more dynamic workflow.

Example one: Lets say that you have designed a magazine and converted all the photos for uncoated paper. One day before print the customer change her mind and want to print on glossy paper instead. This would just take 3 minutes to do this in if you are using InDesign colormanagement. Otherwise you would have to open all original photos in photoshop again and convert them to the coated CMYK-profile, update all links etc. Guessing this would take a lot more then 3 minutes.

Example two: You are making an ad and want to print this in different papers/magazines. If you using InDesign colormanagement you would only need one document and just change document CMYK before output to PDF.

Example three: Your client comes to your office and would like to see how the product would look on various papers. If using InDesign colormanagement you could preview this straight in InDesign on your calibrated display in seconds, without even printing a hard proof on paper.

And on it goes...

 

[cosmo]

If you do an export with convert to destination it will change the CMYK values of a CMYK image or vector to the corresponding icc profile values, ie if you export with convert to destintation to uncoated profile it will change the CMYK & RGB values to that profile, best to leave it with numbers preserved if you dont want to mess with CMYK, preserve numbers will still give you a good CMYK output of RGB. And set it to the desired standard, ie fogra39, preserving numbers will let you change it to another profile without loosing the original color numbers (LAB).

 

[Stephen Marsh]

Here are Adobe’s descriptions of what takes place (image attached).

If the layout contains *vector* 0r0g0b objects such as black text or rules/strokes, then it is best to output from InDesign with No Colour Conversion to retain RGB content so that it can be intelligently converted in Acrobat Pro - based on whether it is raster, vector or text.

If the layout only has RGB raster images and all native and imported vectors/text are greyscale or CMYK mode, then Convert to Destination (Preserve Numbers) would be OK to use.

I personally prefer to do colour conversions in Acrobat Pro, as the rudimentary colour conversion options in InDesign are good for productivity however they can lead to poorly created PDF files.


Stephen Marsh

 

[Magnus]

Here are Adobe’s descriptions of what takes place (image attached).

I personally prefer to do colour conversions in Acrobat Pro, as the rudimentary colour conversion options in InDesign are good for productivity however they can lead to poorly created PDF files.

Stephen Marsh

Im guessing that you are exporting to PDF/x4 in that case? You wouldn't want to loose any embedded ICC-profiles.
We use both PDF/X4 and PDF/X1a depending on the output device/RIP. But in both cases it's really important NOT to turn Color Manangement off in Indesign.

 

[Stephen Marsh]

Im guessing that you are exporting to PDF/x4 in that case? You wouldn't want to loose any embedded ICC-profiles.
We use both PDF/X4 and PDF/X1a depending on the output device/RIP. But in both cases it's really important NOT to turn Color Manangement off in Indesign.

Colour management and colour conversions when exporting PDF files are two different things, although they can of course be related too!

I was not talking of any specific PDF/X standard, just commenting that the InDesign colour conversion tools are more like a machete than a scalpel.

EDIT: Even if creating a PDF/X-1a file, I would advise to change the default and convert with no colour conversion in the InDesign PDF export, then to fix the RGB vector/text conversions in Acrobat Pro and convert the PDF into a PDF/X-1a compliant file in Acrobat Pro (built-in preflight), rather than have InDesign butcher the RGB black text or rules into rich black. Of course, if there are no RGB vector or text black objects, then InDesign can’t butcher them anyway!


Stephen Marsh

 

[Magnus]

If you know what you are doing that could of course be a good solution. I would say most people don't.
At our printshop we are getting too many untagged or faulty converted PDF's that could result in bad looking print. So I think it's much better to teach the client's how to set up correct color settings and export a good PDF (were we can correct any minor issues like rich black in our prepress-system) than to scare people by saying that InDesign is a machete. That will just make more people to turn of all color settings and hope for the best. And if the print looks crappy it's the printers fault.

 

[Stephen Marsh]

Hi Magnus, I think that many workflow systems beyond Acrobat Pro can automatically/seamlessly convert 0r0g0b vectors and text to 0cmy100k without any extra work (it is expected as par for course).

I appreciate that you may prefer to accept say a PDF/X-1a file that could possibly have RGB vectors and text converted to CMYK rich black - rather than accept RGB in the file.

Of course, this would all be a non existent issue if InDesign had an Acrobat Pro “preserve black” feature in it’s colour conversion options, that would cleanly convert 0r0g0b text and vector values to 0cmy100k.


Stephen Marsh

 

[Lukas Engqvist]

If there is transparency involved then there will be a colour conversion that may affect the TAC even if preserve numbers is involved. A Photoshop file with a alpha mask falls into that category. With the colour settings that you have, you can use the separations in InDesign to see what will happen, even the ink coverage to see where the TAC is.

The setting is a standard setting for when RGB objects are colour managed and CMYK objects are used for line art and text where pure colours or clean black is required. It is best for workflows that use in-rip-trapping.

Yes, Acrobat does allow RGB black to be K only, but it will convert all images, and I have found some images (especially those with JPG artifacts ) get too heavy GCR treatment with preserve black setting. Great for screen dumps though.

If you want to limit to one TAC and have demands for an ICC with a different TAC… and you KNOW that they are built on the same characterisation data then you can create a PDF using your low TAC profile and then assign the "standard" profile. This is not the the formally correct way, but assigning a profile built from the same characterisation data is fairly safe.

 

[Stephen Marsh]

Yes, Acrobat does allow RGB black to be K only, but it will convert all images, and I have found some images (especially those with JPG artifacts ) get too heavy GCR treatment with preserve black setting. Great for screen dumps though.

Lukas, I have not noticed the “preserve black” setting messing with images, AFAIK it only affects text/vectors (I have done difference blend tests and there is no difference for images converted using preserve black setting on or off).

Part of the reason that I say that Acrobat Pro is like a scalpel, is the surgical precision that it brings to colour conversions.

One can of course convert everything - or only convert, images, or text, line art or smooth shades/gradients.

One can convert everything or only convert RGB, or only greyscale, or only CMYK etc.

If one is converting text, one can convert text that is between a min/max text size.

Then there are the “preserve black, promote grey to CMYK black and preserve primary CMYK options”.

There are so many ways to slice and dice colour conversions in Acrobat Pro, and this is just with the basic “convert colours” tool.

Then there are Acrobat preflights and fixes.

Then with third party add ons like Enfocus PitStop Pro or full workflow software such as Kodak Prinergy, one has even more tools available.


Stephen Marsh