InDesign CS3 - overprint error

[pantone292]

A client provided a print ready PDF for an 8.5 x 11, 4/4 trifold brochure. Viewing the file in Acrobat it separates correctly; everything looks fine.

We're a small shop. We digitally strip our press jobs in InDesign. When the PDF was stripped up in InDesign for a work and turn run, the way the file was separating changed. The PDF file had a black solid, 100% K and 40% Cyan. There was one black photo within the PDF file. In separations preview in InDesign, when you clicked the black channel off the photo would disappear, but it was NOT knocking out of the cyan. Meaning the black photo was overprinting on top of the 40% Cyan screen that was behind it. Now here's the weird part: the original PDF file when viewed in Acrobat showed the black photo as knocking out, yet once the PDF was placed in InDesign it switched. I couldn't figure out why this was happening. Any thoughts?

I ended up exporting the InDesign file as a PDF and then correcting the overprint problem in Pitstop. Fixed the problem, but still a very weird thing to happen.

Additional info: the PDF file was originally created in Quark.

 

[T]

Was Overprint preview checked on in Acrobat when you were looking at the original PDF file? - OR - Did you make sure and uncheck the "Always overprint 100% black" preference in InDesign?

T

 

[rich apollo]

Did you make sure and uncheck the "Always overprint 100% black" preference in InDesign?

T

Wouldn't that only affect native elements?