Black (K = 100) text in InDesign being reported as CMYK in Acrobat

[Guy Burns]

These are the settings in my InDesign documents:

• CMYK working color space: US Sheetfed Uncoated v2
• Preserve embedded profiles
• Text set to K = 100

When I exported to PDF, these were the settings under Output > Color:

• No color conversion
• Include all profiles

I opened the document in Acrobat and went to Advanced > Output Preview to make sure that what was supposed to be grayscale was grayscale. When I ran the pointer over the text, it came up in CMYK values and not K = 100. That was a surprise. When I changed the SIMULATION PROFILE in the OUTPUT PREVIEW window to US Sheetfed Uncoated v2 (the same profile as in InDesign) the text was listed as K = 100. I assumed the reading being given was actually the color numbers, not 'mapped' color numbers i.e. the color numbers if they were converted to the new space.

Anyway, it was obvious I wasn't on top of this, so I went to ADVANCED > PREFLIGHT >LIST ALL NON BW OBJECTS to check what was BW and what was not. Up came several hundred items, including every font in the document.

I could force the text to BW, but I had to go back to InDesign and change the settings (Output > Color) to:

• No color conversion
i• Don't include profiles

Aha! When I repeated the above tests in Acrobat, no matter what simulation profile I chose, text was always shown as K = 100. A list of all non-BW objects listed only color images -- just what I wanted.

I need a few hints on why this occurred.

QUES: Why should including a colour profile when exporting from InDesign cause K = 100 to map to CMYK? Surely the color numbers going to Acrobat are unaltered out of InDesign (i.e. K = 100 is sent as K = 100) so Acrobat must be changing them. InDesign says of "No Color Conversion": "Uses existing color numbers and doesn't convert them". So why does Acrobat report them as changed?

[unknown]

Don't change the color management settings from the press setting. For
99.9999% of cases it works just fine.

It converts RGB to CMYK and leaves CMYK alone, simply honoring the
numbers otherwise you're leaving yourself open to a CMYK to CMYK
conversion and you've already seen the result...it's not good.

I'm not a color management expert, but the bottom line here is if it
ain't broke, don't fix it.

Bob

[rob day]

Guy,
You only need to include a profile if you need to convert to another CMYK space when the PDF is output—a typical case for including profiles would be one where you don't really know what the print destination is and your CMYK values might need to be reconverted at output. If you don't want additional CMYK conversions (you know the correct destination is US Sheefed) then export as PDFX/1-a, that preset includes an intent but not a profile and your black will not get converted.

Unwanted color conversions indicate that there are conflicting profiles somewhere.