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