PDF flat tint readings different

[lnivin]

We have an InDesign CS4 file with PMS 877 as a solid tint and artwork filled with a 75% tint. PDF was exported with no color management.

Checking the color in Acrobat 8 --> Output Preview the tint reads 85%.

In PitStop the tint reads 75% of PMS 877.

On plate, it reads 85% dot.

What's going on?

 

[CHM]

We have an InDesign CS4 file with PMS 877 as a solid tint and artwork filled with a 75% tint. PDF was exported with no color management.

Checking the color in Acrobat 8 --> Output Preview the tint reads 85%.

In PitStop the tint reads 75% of PMS 877.

On plate, it reads 85% dot.

What's going on?

Did you test this in Illustrator to?
Do you have the same there?

 

[lnivin]

Yes. Illustrator reads the tint as 75%.

I believe the Output Preview is adding dot gain.

Thanks,

 

[leonardr]

Yes. Illustrator reads the tint as 75%.

I believe the Output Preview is adding dot gain.,

Output Preview does not do that.

You will need to post the PDF itself for us to be able to make any decisions about it - anything else is a GUESS!

 

[rich apollo]

The Output Preview doesn't show actual file values. It passes the artwork from the source colorspace (either embedded in the file/element, attached as an Output Intent, or the default according to the color settings/Color Management Preferences) to the destination colorspace (as selected in the Output Preview panel).

That being said, in the testing I'm doing (with Acrobat 9) a spot color doesn't register any change in the Output Preview - only process colors.

As to why you're reading an 85% on plate, there are several areas where that could occur, but Output Preview isn't one of them.

Looking at the PDF I could tell you more.

 

[lnivin]

I can't believe we haven't noticed this before, but it is the icc profile causing the difference. If I strip out ICC tags using PitStop Action, everything reads correctly.

I don't seem to have at Attachment option.

 

[Stephen Marsh]

The Output Preview doesn't show actual file values.

Rich, I could be mistaken, however your comment above does not fit in with my experience.



Sincerely,

Stephen Marsh

 

[rich apollo]

Stephen,
Switching the profile in the Output Preview panel causes different readings in the Output Preview panel whenever I have played with it. It doesn't change the file values, but gives an indication of what the file values would be if you converted to the profile listed in the panel.

 

[Stephen Marsh]

Stephen,
Switching the profile in the Output Preview panel causes different readings in the Output Preview panel whenever I have played with it. It doesn't change the file values, but gives an indication of what the file values would be if you converted to the profile listed in the panel.

Agreed Rich!

The KEY issue is the use and misuse of the "Simulation Profile" drop down menu option.

By default, this simulation profile will list the default CMYK working space set in colour settings.

* If a PDF is untagged with no ICC profile, simply leaving this option alone and letting it default will indicate the correct file values for tints and solids.

* If a PDF has a CMYK profile assigned to it, then the simulation profile MUST match the tagged ICC profile, otherwise as you say, the reported values will be "converted" (without the actual file values changing)

So, the Output Preview readings MAY or MAY NOT report the actual file values, depending on the source ICC profile (or lack there of) and the selected Simulation Profile setting.

I am sure that this could be better designed or explained in the interface or the manual. I am also sure that we could have a very long and productive topic thread discussing this critical feature of Acrobat Pro (or perhaps that would be better discussed at the Adobe forum for Acrobat feature requests)!


Sincerely,

Stephen Marsh

 

[leonardr]

The KEY issue is the use and misuse of the "Simulation Profile" drop down menu option.

By default, this simulation profile will list the default CMYK working space set in colour settings.

For PDFs that do not comply with any of the ISO "subset standards" (aka PDF/X, PDF/A and PDF/E), this is correct - the default profile will be the CMYK working space. For any standards-compliant file, the embedded OutputIntent profile will be used.

* If a PDF is untagged with no ICC profile, simply leaving this option alone and letting it default will indicate the correct file values for tints and solids.
* If a PDF has a CMYK profile assigned to it, then the simulation profile MUST match the tagged ICC profile, otherwise as you say, the reported values will be "converted" (without the actual file values changing)

A PDF is not "tagged" or "untagged". Each individual graphic object in the file can have an associated profile if it is described using ICCBased colourspace, however, it can also use any of other 10 colourspaces available in the PDF format. Some are device colourants and some are device independent.

That said, the values displayed by Output Preview are ALWAYS taken through the profile selected in the UI - as Rich said - because PDF is a colour managed format. Even if you only work with CMYK and Spots - you're still doing so in a colour managed world.

I am sure that this could be better designed or explained in the interface or the manual. I am also sure that we could have a very long and productive topic thread discussing this critical feature of Acrobat Pro (or perhaps that would be better discussed at the Adobe forum for Acrobat feature requests)!

Always open for suggestions on how to make our products better...

Leonard

 

[buckeye]

I've always felt the same way as Rich about the Output Preview being misleading. After Stephens' reply, it makes a little more sense to me now on its use, and leonardr after reading your post a couple of times, even more sense. Thanks.

Erik

 

[Stephen Marsh]

For PDFs that do not comply with any of the ISO "subset standards" (aka PDF/X, PDF/A and PDF/E), this is correct - the default profile will be the CMYK working space. For any standards-compliant file, the embedded OutputIntent profile will be used.

Thanks for the reply Leonardr, agreed.

For my examples above I should have stated that I was not talking about the ISO PDF files that you mention.

A PDF is not "tagged" or "untagged". Each individual graphic object in the file can have an associated profile if it is described using ICCBased colourspace, however, it can also use any of other 10 colourspaces available in the PDF format. Some are device colourants and some are device independent.

Perhaps I should not have used such "loose" terms.

I was not really talking about global "tagging" (ala Photoshop), but object ICC tags...such as are displayed when one uses the object inspector found in the output preview.

How should one describe native vector elements in an InDesign file that are setup using Device CMYK, then exported in a PDF that contains no ICC profiles?

How should one describe native vector element CMYK objects in a PDF from InDesign that has a document CMYK profile assigned to it and is then exported with "include all profiles"?

That said, the values displayed by Output Preview are ALWAYS taken through the profile selected in the UI - as Rich said - because PDF is a colour managed format. Even if you only work with CMYK and Spots - you're still doing so in a colour managed world.

Agreed, however depending on the choice of the simulation profile selected in the UI and the ICC content of of the source file, the output preview can report wildly different values for the elements in the file. This can lead to some confusion on what values the file actually contains (as in is that body text really 0cmy100K or not?).


Regards,

Stephen Marsh

 

[rich apollo]

For PDFs that do not comply with any of the ISO "subset standards" (aka PDF/X, PDF/A and PDF/E), this is correct - the default profile will be the CMYK working space. For any standards-compliant file, the embedded OutputIntent profile will be used.

For discussion's sake, if you export a PDF/X-4 file, you can choose to embed all profiles and not to convert anything. So, you could have elements with embedded profiles that differ from the Output Intent. The Output Preview panel would show you the potential file values for the element being taken from the colorspace described by the embedded ICC profile and into the colorspace described by the Output Intent (using the default Rendering Intent specified in the Color Management preferences).

I'd like to be able to see actual file values, color space descriptions (RGB, spot color, ICC profile, et cetera), and I'd like to be able to specify the Rendering Intent in the Preview panel.

 

[Stephen Marsh]

With overnight reflection, I think that I have answered my own questions/doubts about the separations preview section of output preview...I should not be using it as often as I do for CMYK elements, it would seem that I would be better served using the object inspector for CMYK so that I know the file values that I am reading are not being influenced by a transform between a source and destination profile.

Separations preview for non ISO PDF files would appear to only really be safe for evaluating the files CMYK "original" or "input" values when one is sure that the original is not colour managed by ICC profiles, or that if using an ICC profile that a "null conversion" is taking place - which can be tedious to ensure.


Stephen Marsh

 

[Lukas Engqvist]

Great discussion. Personally I teach an RGB for colour managed and Safe CMYK (All CMYK treated as preserve values) to keep things managable. Combined with a PDFx1 or PDFx4 this is managable.
I sometimes forget that we can make the world more complex than that
As Einstein said, make things as simple as you can but no simpler.

 

[Stephen Marsh]

Great discussion. Personally I teach an RGB for colour managed and Safe CMYK (All CMYK treated as preserve values) to keep things managable. Combined with a PDFx1 or PDFx4 this is managable.
I sometimes forget that we can make the world more complex than that
As Einstein said, make things as simple as you can but no simpler.

Agreed Lukas, this is very workable solution for many. Sadly, as you know, often PDF files come in without the supplier checking first on what joboptions file should be used for the PDF creation (or the PDF may be generated by some "other" application). The PDF and it's content are a mystery.

When preflighting an unknown PDF file, I use a combination of methods - automated preflight rules that are built into Acrobat, Enfocus InstantPDF and manual inspection.

It is the manual inspection using the Acrobat Pro Output Preview Separations Preview that can become tricky at times when getting info on colour builds. I am now going to make greater use of the Object Inspector option of the Output Preview palette!


Best,

Stephen Marsh

 

[leonardr]

I'd like to be able to see actual file values, color space descriptions (RGB, spot color, ICC profile, et cetera),

That's what the Object Inspector does. It will show you the "raw" colour values, colour spaces (ICC profile names, if applicable),. etc. Of course, for images, there are multiple values, so it doesn't help on that - but for vector and text, the raw values might be useful.

and I'd like to be able to specify the Rendering Intent in the Preview panel.

Again, with PDF, EACH OBJECT can have a specified rendering intent associated with it. If there is an explicit one provided, that will also be listed in the Object Inspector.

If you want to change it, you can use the Touchup Object tool. choose "Properties" on the context menu and then go to the Color panel. This has been in Acrobat since version 6, I believe.

 

[rich apollo]

That's what the Object Inspector does. It will show you the "raw" colour values, colour spaces (ICC profile names, if applicable),. etc. Of course, for images, there are multiple values, so it doesn't help on that - but for vector and text, the raw values might be useful.

Thanks, Leonard! I honestly never clicked on it.

So, what is the logic behind an object having an embedded Rendering Intent?

 

[leonardr]

So, what is the logic behind an object having an embedded Rendering Intent?

You might want to render a specific image via Saturation intent w/o impacting the rest of the content.

 

[rich apollo]

So, where could one take advantage of an embedded Rendering Intent? The tools in Acrobat allow you specify a Rendering Intent or use one embedded in the document, but make no reference to a Rendering Intent embedded in an individual object.

PitStop (v8) shows the same limitations. Are there other tools that can make use of an embedded Rendering Intent?