- Using InDesign I created the interior of a 352-page book. It is supposed to be black only. But some of the diagrams in the book have hidden CMYK values.
- I created a PDF from InDesign. The PDF retains the hidden CMYK values.
- How can I convert my PDF into one that is black ink only, with no CMYK or color values? Is there a simple way to do this in Acrobat?
Ideally, you would alter the images placed in InDesign using their native applications - Photoshop/Illustrator - then replace them (or update the links to them) in the InDesign layout and regenerate the PDFs needed.
Conversion to Grayscale from CMYK can often result in various percentages of black and rarely will result in 100% black if that's the desired percentage. The only way to ensure 100% black is 100% black is to make certain the original artwork is set to use that color and percentage.
You can do this really easily by using the preflight option in Acrobat. In the 'Prepress, Colour and Transparency' fixes menu, search for 'Correct 4C Black' - this will identify any 4C black in your document and then change it to 100% K
You can specify if it's text and vectors, vectors, just text, images, etc. you want changed as well, which is great.